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  • 1.
    Amrein, Beat A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Duarte, Fernanda
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Janfalk Carlsson, Åsa
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Naworyta, Agata
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mowbray, Sherry L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Kamerlin, Shina C. L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Expanding the catalytic triad in epoxide hydrolases and related enzymes2015In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 5, no 10, p. 5702-5713Article in journal (Refereed)
    Abstract [en]

    Potato epoxide hydrolase 1 exhibits rich enantio- and regioselectivity in the hydrolysis of a broadrange of substrates. The enzyme can be engineered to increase the yield of optically pureproducts, as a result of changes in both enantio- and regioselectivity. It is thus highly attractive inbiocatalysis, particularly for the generation of enantiopure fine chemicals and pharmaceuticals.The present work aims to establish the principles underlying the activity and selectivity of theenzyme through a combined computational, structural, and kinetic study, using the substratetrans-stilbene oxide as a model system. Extensive empirical valence bond simulations have beenperformed on the wild-type enzyme together with several experimentally characterized mutants.We are able to computationally reproduce the differences in activities between differentstereoisomers of the substrate, and the effects of mutations in several active-site residues. Inaddition, our results indicate the involvement of a previously neglected residue, H104, which iselectrostatically linked to the general base, H300. We find that this residue, which is highlyconserved in epoxide hydrolases and related hydrolytic enzymes, needs to be in its protonatedform in order to provide charge balance in an otherwise negatively-charged active site. Our datashow that unless the active-site charge balance is correctly treated in simulations, it is notpossible to generate a physically meaningful model for the enzyme that can accurately reproduceactivity and selectivity trends. We also expand our understanding of other catalytic residues,demonstrating in particular the role of a non-canonical residue, E35, as a “backup-base” in theabsence of H300. Our results provide a detailed view of the main factors driving catalysis andregioselectivity in this enzyme, and identify targets for subsequent enzyme design efforts.

  • 2.
    Barrozo, Alexandre
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Duarte, Fernanda
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Carvalho, Alexandra T. P.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Kamerlin, Shina C. Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Cooperative Electrostatic Interactions Drive Functional Evolution in the Alkaline Phosphatase Superfamily2015In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, no 28, p. 9061-9076Article in journal (Refereed)
    Abstract [en]

    It is becoming widely accepted that catalytic promiscuity, i.e., the ability of a single enzyme to catalyze the turnover of multiple, chemically distinct substrates, plays a key role in the evolution of new enzyme functions. In this context, the members of the alkaline phosphatase superfamily have been extensively studied as model systems in order to understand the phenomenon of enzyme multifunctionality. In the present work, we model the selectivity of two multiply promiscuous members of this superfamily, namely the phosphonate monoester hydrolases from Burkholderia caryophylli and Rhizobium leguminosarum. We have performed extensive simulations of the enzymatic reaction of both wild-type enzymes and several experimentally characterized mutants. Our computational models are in agreement with key experimental observables, such as the observed activities of the wild-type enzymes, qualitative interpretations of experimental pH-rate profiles, and activity trends among several active site mutants. In all cases the substrates of interest bind to the enzyme in similar conformations, with largely unperturbed transition states from their corresponding analogues in aqueous solution. Examination of transition-state geometries and the contribution of individual residues to the calculated activation barriers suggest that the broad promiscuity of these enzymes arises from cooperative electrostatic interactions in the active site, allowing each enzyme to adapt to the electrostatic needs of different substrates. By comparing the structural and electrostatic features of several alkaline phosphatases, we suggest that this phenomenon is a generalized feature driving selectivity and promiscuity within this superfamily and can be in turn used for artificial enzyme design.

  • 3.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Computational modelling of enzyme selectivity2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Enantioselective reactions are one of the ways to produce pure chiral compounds. Understanding the basis of this selectivity makes it possible to guide enzyme design towards more efficient catalysts. One approach to study enzymes involved in chiral chemistry is through the use of computational models that are able to simulate the chemical reaction taking place. The potato epoxide hydrolase is one enzyme that is known to be both highly enantioselective, while still being robust upon mutation of residues to change substrate scope. The enzyme was used to investigate the epoxide hydrolysis mechanism for a number of different substrates, using the EVB approach to the reaction both in solution and in several enzyme variants. In addition to this, work has been performed on new ways of performing simulations of divalent transition metals, as well as development of new simulation software.

    List of papers
    1. Force Field Independent Metal Parameters Using a Nonbonded Dummy Model
    Open this publication in new window or tab >>Force Field Independent Metal Parameters Using a Nonbonded Dummy Model
    Show others...
    2014 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 16, p. 4351-4362Article in journal (Refereed) Published
    Abstract [en]

    The cationic dummy atom approach provides a powerful nonbonded description for a range of alkaline-earth and transition-metal centers, capturing both structural and electrostatic effects. In this work we refine existing literature parameters for octahedrally coordinated Mn2+, Zn2+, Mg2+, and Ca2+, as well as providing new parameters for Ni2+, Co2+, and Fe2+. In all the cases, we are able to reproduce both M2+-O distances and experimental solvation free energies, which has not been achieved to date for transition metals using any other model. The parameters have also been tested using two different water models and show consistent performance. Therefore, our parameters are easily transferable to any force field that describes nonbonded interactions using Coulomb and Lennard-Jones potentials. Finally, we demonstrate the stability of our parameters in both the human and Escherichia coli variants of the enzyme glyoxalase 1 as showcase systems, as both enzymes are active with a range of transition metals. The parameters presented in this work provide a valuable resource for the molecular simulation community, as they extend the range of metal ions that can be studied using classical approaches, while also providing a starting point for subsequent parametrization of new metal centers.

    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-225523 (URN)10.1021/jp501737x (DOI)000335113600010 ()
    Funder
    Swedish National Infrastructure for Computing (SNIC), 2013/26-1
    Available from: 2014-06-23 Created: 2014-06-04 Last updated: 2018-12-03Bibliographically approved
    2. Expanding the catalytic triad in epoxide hydrolases and related enzymes
    Open this publication in new window or tab >>Expanding the catalytic triad in epoxide hydrolases and related enzymes
    Show others...
    2015 (English)In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 5, no 10, p. 5702-5713Article in journal (Refereed) Published
    Abstract [en]

    Potato epoxide hydrolase 1 exhibits rich enantio- and regioselectivity in the hydrolysis of a broadrange of substrates. The enzyme can be engineered to increase the yield of optically pureproducts, as a result of changes in both enantio- and regioselectivity. It is thus highly attractive inbiocatalysis, particularly for the generation of enantiopure fine chemicals and pharmaceuticals.The present work aims to establish the principles underlying the activity and selectivity of theenzyme through a combined computational, structural, and kinetic study, using the substratetrans-stilbene oxide as a model system. Extensive empirical valence bond simulations have beenperformed on the wild-type enzyme together with several experimentally characterized mutants.We are able to computationally reproduce the differences in activities between differentstereoisomers of the substrate, and the effects of mutations in several active-site residues. Inaddition, our results indicate the involvement of a previously neglected residue, H104, which iselectrostatically linked to the general base, H300. We find that this residue, which is highlyconserved in epoxide hydrolases and related hydrolytic enzymes, needs to be in its protonatedform in order to provide charge balance in an otherwise negatively-charged active site. Our datashow that unless the active-site charge balance is correctly treated in simulations, it is notpossible to generate a physically meaningful model for the enzyme that can accurately reproduceactivity and selectivity trends. We also expand our understanding of other catalytic residues,demonstrating in particular the role of a non-canonical residue, E35, as a “backup-base” in theabsence of H300. Our results provide a detailed view of the main factors driving catalysis andregioselectivity in this enzyme, and identify targets for subsequent enzyme design efforts.

    National Category
    Biochemistry and Molecular Biology
    Research subject
    Biochemistry
    Identifiers
    urn:nbn:se:uu:diva-260232 (URN)10.1021/acscatal.5b01639 (DOI)000362391500006 ()
    Funder
    EU, FP7, Seventh Framework Programme, 306474Swedish Research Council, 621-2011-6055, 621-2010-5145Swedish National Infrastructure for Computing (SNIC), 2015/16-12
    Available from: 2015-08-18 Created: 2015-08-18 Last updated: 2017-12-04Bibliographically approved
    3. Conformational Diversity and Enantioconvergence in Potato Epoxide Hydrolase 1
    Open this publication in new window or tab >>Conformational Diversity and Enantioconvergence in Potato Epoxide Hydrolase 1
    Show others...
    2016 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 14, no 24, p. 5639-5651Article in journal (Refereed) Published
    Abstract [en]

    Potato epoxide hydrolase 1 (StEH1) is a biocatalytically important enzyme that exhibits rich enantio-and regioselectivity in the hydrolysis of chiral epoxide substrates. In particular, StEH1 has been demonstrated to enantioconvergently hydrolyze racemic mixes of styrene oxide (SO) to yield (R)-1-phenylethanediol. This work combines computational, crystallographic and biochemical analyses to understand both the origins of the enantioconvergent behavior of the wild-type enzyme, as well as shifts in activities and substrate binding preferences in an engineered StEH1 variant, R-C1B1, which contains four active site substitutions (W106L, L109Y, V141K and I155V). Our calculations are able to reproduce both the enantio-and regioselectivities of StEH1, and demonstrate a clear link between different substrate binding modes and the corresponding selectivity, with the preferred binding modes being shifted between the wild-type enzyme and the R-C1B1 variant. Additionally, we demonstrate that the observed changes in selectivity and the corresponding enantioconvergent behavior are due to a combination of steric and electrostatic effects that modulate both the accessibility of the different carbon atoms to the nucleophilic side chain of D105, as well as the interactions between the substrate and protein amino acid side chains and active site water molecules. Being able to computationally predict such subtle effects for different substrate enantiomers, as well as to understand their origin and how they are affected by mutations, is an important advance towards the computational design of improved biocatalysts for enantioselective synthesis.

    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-282015 (URN)10.1039/C6OB00060F (DOI)000378933400042 ()27049844 (PubMedID)
    Funder
    Swedish National Infrastructure for Computing (SNIC), 25/2-10EU, European Research Council, 306474;283570Swedish Research Council, 621-2011-6055Carl Tryggers foundation , CTS13:104
    Available from: 2016-04-01 Created: 2016-04-01 Last updated: 2017-11-30Bibliographically approved
    4. Laboratory evolved enzymes provide snapshots of the development of enantioconvergence in enzyme-catalyzed epoxide hydrolysis
    Open this publication in new window or tab >>Laboratory evolved enzymes provide snapshots of the development of enantioconvergence in enzyme-catalyzed epoxide hydrolysis
    Show others...
    2016 (English)In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 17, no 18, p. 1693-1697Article in journal (Refereed) Published
    Abstract [en]

    Engineered enzyme variants of potato epoxide hydrolase (StEH1) display varying degrees of enrichment of (2R)-3-phenylpropane-1,2-diol from racemic benzyloxirane. Curiously, the observed increase in the enantiomeric excess of the (R)-diol is not only due to changes in enantioselectivity for the preferred epoxide enantiomer, but also to changes in the regioselectivity of the epoxide ring opening of (S)-benzyloxirane. To probe the structural origin of these differences in substrate selectivities and catalytic regiopreferences, we have solved the crystal structures for the in-vitro evolved StEH1 variants. We have additionally used these structures as a starting point for docking the epoxide enantiomers into the respective active sites. Interestingly, despite the simplicity of our docking calculations, the apparent preferred binding modes obtained from the docking appears to rationalize the experimentally determined regioselectivities. These calculations could also identify an active site residue (F33) as a putatively important interaction partner, a role that could explain the high degree of conservation of this residue during evolution. Overall, our combined experimental, structural and computational studies of this system provide snapshots into the evolution of enantioconvergence in StEH1 catalyzed epoxide hydrolysis.

    Keywords
    enantioselectivity; epoxide hydrolysis; evolutionary snapshots; laboratory evolution; protein engineering
    National Category
    Biochemistry and Molecular Biology
    Research subject
    Biochemistry
    Identifiers
    urn:nbn:se:uu:diva-298675 (URN)10.1002/cbic.201600330 (DOI)000384425400004 ()27383542 (PubMedID)
    Funder
    Swedish Research CouncilEU, European Research Council, 306474Swedish National Infrastructure for Computing (SNIC), SNIC2015-16-12EU, FP7, Seventh Framework Programme, 283570
    Available from: 2016-07-06 Created: 2016-07-06 Last updated: 2017-11-28Bibliographically approved
    5. Epoxide Hydrolysis as a Model System for Understanding Flux Through a Branched Reaction Scheme
    Open this publication in new window or tab >>Epoxide Hydrolysis as a Model System for Understanding Flux Through a Branched Reaction Scheme
    Show others...
    2018 (English)In: IUCrJ, ISSN 0972-6918, E-ISSN 2052-2525, Vol. 5, no 3, p. 269-282Article in journal (Refereed) Published
    Abstract [en]

    The epoxide hydrolase StEH1 catalyzes the hydrolysis of trans-methylstyrene oxide to 1-phenyl­propane-1,2-diol. The (S,S)-epoxide is exclusively transformed into the (1R,2S)-diol, while hydrolysis of the (R,R)-epoxide results in a mixture of product enantiomers. In order to understand the differences in the stereoconfigurations of the products, the reactions were studied kinetically during both the pre-steady-state and steady-state phases. A number of closely related StEH1 variants were analyzed in parallel, and the results were rationalized by structure–activity analysis using the available crystal structures of all tested enzyme variants. Finally, empirical valence-bond simulations were performed in order to provide additional insight into the observed kinetic behaviour and ratios of the diol product enantiomers. These combined data allow us to present a model for the flux through the catalyzed reactions. With the (R,R)-epoxide, ring opening may occur at either C atom and with similar energy barriers for hydrolysis, resulting in a mixture of diol enantiomer products. However, with the (S,S)-epoxide, although either epoxide C atom may react to form the covalent enzyme intermediate, only the pro-(R,S) alkylenzyme is amenable to subsequent hydrolysis. Previously contradictory observations from kinetics experiments as well as product ratios can therefore now be explained for this biocatalytically relevant enzyme.

    National Category
    Biochemistry and Molecular Biology
    Research subject
    Biochemistry
    Identifiers
    urn:nbn:se:uu:diva-343750 (URN)10.1107/S2052252518003573 (DOI)000431151300004 ()29755743 (PubMedID)
    Funder
    Swedish Research CouncilEU, FP7, Seventh Framework Programme
    Available from: 2018-03-01 Created: 2018-03-01 Last updated: 2018-12-03Bibliographically approved
    6. Q Version 6, a comprehensive toolkit for empirical valence bond and related free energy calculations.
    Open this publication in new window or tab >>Q Version 6, a comprehensive toolkit for empirical valence bond and related free energy calculations.
    Show others...
    (English)Manuscript (preprint) (Other academic)
    National Category
    Other Chemistry Topics
    Identifiers
    urn:nbn:se:uu:diva-325490 (URN)
    Available from: 2017-07-02 Created: 2017-07-02 Last updated: 2017-07-03
  • 4.
    Bauer, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Barrozo, Alexandre
    Department of Chemistry, University of Southern California, SGM 418, 3620 McClintock Ave., Los Angeles, CA 90089-1062, United StatesDepartment of Chemistry, University of Southern California, SGM 418, 3620 McClintock Ave., Los Angeles, CA 90089-1062, United States.
    Purg, Miha
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Amrein, Beat Anton
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Esguerra, Mauricio
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Wilson, Philippe Barrie
    Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester LE1 9BH, UK.
    Major, Dan Thomas
    Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel.
    Åqvist, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Kamerlin, Shina C. Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology.
    Q6: A comprehensive toolkit for empirical valence bond and related free energy calculations2018In: SoftwareX, ISSN 2352-7110, p. 388-395Article in journal (Refereed)
    Abstract [en]

    Atomistic simulations have become one of the main approaches to study the chemistry and dynamicsof biomolecular systems in solution. Chemical modelling is a powerful way to understand biochemistry,with a number of different programs available to perform specialized calculations. We present here Q6, anew version of the Q software package, which is a generalized package for empirical valence bond, linearinteraction energy, and other free energy calculations. In addition to general technical improvements, Q6extends the reach of the EVB implementation to fast approximations of quantum effects, extended solventdescriptions and quick estimation of the contributions of individual residues to changes in the activationfree energy of reactions.

  • 5.
    Bauer, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology.
    Janfalk Carlsson, Åsa
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Amrein, Beat A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology.
    Dobritzsch, Doreen
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Kamerlin, S. C. Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology.
    Conformational Diversity and Enantioconvergence in Potato Epoxide Hydrolase 12016In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 14, no 24, p. 5639-5651Article in journal (Refereed)
    Abstract [en]

    Potato epoxide hydrolase 1 (StEH1) is a biocatalytically important enzyme that exhibits rich enantio-and regioselectivity in the hydrolysis of chiral epoxide substrates. In particular, StEH1 has been demonstrated to enantioconvergently hydrolyze racemic mixes of styrene oxide (SO) to yield (R)-1-phenylethanediol. This work combines computational, crystallographic and biochemical analyses to understand both the origins of the enantioconvergent behavior of the wild-type enzyme, as well as shifts in activities and substrate binding preferences in an engineered StEH1 variant, R-C1B1, which contains four active site substitutions (W106L, L109Y, V141K and I155V). Our calculations are able to reproduce both the enantio-and regioselectivities of StEH1, and demonstrate a clear link between different substrate binding modes and the corresponding selectivity, with the preferred binding modes being shifted between the wild-type enzyme and the R-C1B1 variant. Additionally, we demonstrate that the observed changes in selectivity and the corresponding enantioconvergent behavior are due to a combination of steric and electrostatic effects that modulate both the accessibility of the different carbon atoms to the nucleophilic side chain of D105, as well as the interactions between the substrate and protein amino acid side chains and active site water molecules. Being able to computationally predict such subtle effects for different substrate enantiomers, as well as to understand their origin and how they are affected by mutations, is an important advance towards the computational design of improved biocatalysts for enantioselective synthesis.

  • 6.
    Duarte, Fernanda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Barrozo, Alexandre
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Amrein, Beat Anton
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Purg, Miha
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Åqvist, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Kamerlin, Shina Caroline Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Force Field Independent Metal Parameters Using a Nonbonded Dummy Model2014In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 16, p. 4351-4362Article in journal (Refereed)
    Abstract [en]

    The cationic dummy atom approach provides a powerful nonbonded description for a range of alkaline-earth and transition-metal centers, capturing both structural and electrostatic effects. In this work we refine existing literature parameters for octahedrally coordinated Mn2+, Zn2+, Mg2+, and Ca2+, as well as providing new parameters for Ni2+, Co2+, and Fe2+. In all the cases, we are able to reproduce both M2+-O distances and experimental solvation free energies, which has not been achieved to date for transition metals using any other model. The parameters have also been tested using two different water models and show consistent performance. Therefore, our parameters are easily transferable to any force field that describes nonbonded interactions using Coulomb and Lennard-Jones potentials. Finally, we demonstrate the stability of our parameters in both the human and Escherichia coli variants of the enzyme glyoxalase 1 as showcase systems, as both enzymes are active with a range of transition metals. The parameters presented in this work provide a valuable resource for the molecular simulation community, as they extend the range of metal ions that can be studied using classical approaches, while also providing a starting point for subsequent parametrization of new metal centers.

  • 7.
    Hong, Nan-Sook
    et al.
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Petrovic, Dusan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Lee, Richmond
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Gryn'ova, Ganna
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia;Ecole Polytech Fed Lausanne, Inst Sci & Ingn Chim, CH-1015 Lausanne, Switzerland.
    Purg, Miha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Saunders, Jake
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Carr, Paul D.
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Lin, Ching-Yeh
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Mabbitt, Peter D.
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Zhang, William
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Altamore, Timothy
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Easton, Chris
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Coote, Michelle L.
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    Kamerlin, Shina C. Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Jackson, Colin J.
    Australian Natl Univ, Res Sch Chem, Canberra, ACT 2601, Australia.
    The evolution of multiple active site configurations in a designed enzyme2018In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, article id 3900Article in journal (Refereed)
    Abstract [en]

    Developments in computational chemistry, bioinformatics, and laboratory evolution have facilitated the de novo design and catalytic optimization of enzymes. Besides creating useful catalysts, the generation and iterative improvement of designed enzymes can provide valuable insight into the interplay between the many phenomena that have been suggested to contribute to catalysis. In this work, we follow changes in conformational sampling, electrostatic preorganization, and quantum tunneling along the evolutionary trajectory of a designed Kemp eliminase. We observe that in the Kemp Eliminase KE07, instability of the designed active site leads to the emergence of two additional active site configurations. Evolutionary conformational selection then gradually stabilizes the most efficient configuration, leading to an improved enzyme. This work exemplifies the link between conformational plasticity and evolvability and demonstrates that residues remote from the active sites of enzymes play crucial roles in controlling and shaping the active site for efficient catalysis.

  • 8.
    Janfalk Carlsson, Åsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dobritzsch, Doreen
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Kamerlin, Shina C Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Epoxide Hydrolysis as a Model System for Understanding Flux Through a Branched Reaction Scheme2018In: IUCrJ, ISSN 0972-6918, E-ISSN 2052-2525, Vol. 5, no 3, p. 269-282Article in journal (Refereed)
    Abstract [en]

    The epoxide hydrolase StEH1 catalyzes the hydrolysis of trans-methylstyrene oxide to 1-phenyl­propane-1,2-diol. The (S,S)-epoxide is exclusively transformed into the (1R,2S)-diol, while hydrolysis of the (R,R)-epoxide results in a mixture of product enantiomers. In order to understand the differences in the stereoconfigurations of the products, the reactions were studied kinetically during both the pre-steady-state and steady-state phases. A number of closely related StEH1 variants were analyzed in parallel, and the results were rationalized by structure–activity analysis using the available crystal structures of all tested enzyme variants. Finally, empirical valence-bond simulations were performed in order to provide additional insight into the observed kinetic behaviour and ratios of the diol product enantiomers. These combined data allow us to present a model for the flux through the catalyzed reactions. With the (R,R)-epoxide, ring opening may occur at either C atom and with similar energy barriers for hydrolysis, resulting in a mixture of diol enantiomer products. However, with the (S,S)-epoxide, although either epoxide C atom may react to form the covalent enzyme intermediate, only the pro-(R,S) alkylenzyme is amenable to subsequent hydrolysis. Previously contradictory observations from kinetics experiments as well as product ratios can therefore now be explained for this biocatalytically relevant enzyme.

  • 9.
    Janfalk Carlsson, Åsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Ma, Huan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Obtaining optical purity for product diols in enzyme-catalyzed epoxide hydrolysis: contributions from changes in both enantio- and regioselectivity2012In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 51, no 38, p. 7627-7637Article in journal (Refereed)
    Abstract [en]

    Enzyme variants of the plant epoxide hydrolase StEH1 displaying improved stereoselectivities in the catalyzed hydrolysis of (2,3-epoxypropyl)benzene were generated by directed evolution. The evolution was driven by iterative saturation mutagenesis in combination with enzyme activity screenings where product chirality was the decisive selection criterion. Analysis of the underlying causes of the increased diol product ratios revealed two major contributing factors: increased enantioselectivity for the corresponding epoxide enantiomer(s) and, in some cases, a concomitant change in regioselectivity in the catalyzed epoxide ring-opening half-reaction. Thus, variant enzymes that catalyzed the hydrolysis of racemic (2,3-epoxypropyl)benzene into the R-diol product in an enantioconvergent manner were isolated.

  • 10.
    Marsavelski, Aleksandra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Rudjer Boskovic Inst, Div Organ Chem & Biochem, Computat Organ Chem & Biochem Grp, Bijenicka Cesta 54, Zagreb 10000, Croatia;Univ Zagreb, Fac Sci, Dept Chem, Horvatovac 102a, Zagreb 10000, Croatia.
    Petrovic, Dusan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. KTH Royal Inst Technol, Dept Biophys, SciLifeLab, S-10691 Stockholm, Sweden.
    Vianello, Robert
    Rudjer Boskovic Inst, Div Organ Chem & Biochem, Computat Organ Chem & Biochem Grp, Bijenicka Cesta 54, Zagreb 10000, Croatia.
    Kamerlin, Shina Caroline Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology.
    Empirical Valence Bond Simulations Suggest a Direct Hydride Transfer Mechanism for Human Diamine Oxidase2018In: ACS Omega, ISSN 2470-1343, Vol. 3, no 4, p. 3665-3674Article in journal (Refereed)
    Abstract [en]

    Diamine oxidase (DAO) is an enzyme involved in the regulation of cell proliferation and the immune response. This enzyme performs oxidative deamination in the catabolism of biogenic amines, including, among others, histamine, putrescine, spermidine, and spermine. The mechanistic details underlying the reductive half-reaction of the DAO-catalyzed oxidative deamination which leads to the reduced enzyme cofactor and the aldehyde product are, however, still under debate. The catalytic mechanism was proposed to involve a prototropic shift from the substrateSchiff base to the product-Schiff base, which includes the ratelimiting cleavage of the C alpha-H bond by the conserved catalytic aspartate. Our detailed mechanistic study, performed using a combined quantum chemical cluster approach with empirical valence bond simulations, suggests that the rate-limiting cleavage of the C alpha-H bond involves direct hydride transfer to the topaquinone cofactor. a mechanism that does not involve the formation of a Schiff base. Additional investigation of the D373E and D373N variants supported the hypothesis that the conserved catalytic aspartate is indeed essential for the reaction; however, it does not appear to serve as the catalytic base, as previously suggested. Rather, the electrostatic contributions of the most significant residues (including D373), together with the proximity of the Cu2+ cation to the reaction site, lower the activation barrier to drive the chemical reaction.

  • 11.
    Maurer, Dirk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Enugala, Thilak Reddy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Hamnevik, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Lüking, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology.
    Hillier, Heidi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Kamerlin, Shina C. Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dobritzsch, Doreen
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Stereoselectivity in Catalyzed Transformation of a 1,2-Disubstituted Vicinal Diol and the Corresponding Diketone by Wild Type and Laboratory Evolved Alcohol DehydrogenasesIn: Article in journal (Other academic)
  • 12.
    Maurer, Dirk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Enugala, Thilak Reddy
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Hamnevik, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Molecular Cell Biology.
    Lüking, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Petrovic, Dusan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Hillier, Heidi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Kamerlin, Shina C. L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Dobritzsch, Doreen
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Stereo- and Regioselectivity in Catalyzed Transformation of a 1,2-Disubstituted Vicinal Diol and the Corresponding Diketone by Wild Type and Laboratory Evolved Alcohol Dehydrogenases2018In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 8, no 8, p. 7526-7538Article in journal (Refereed)
    Abstract [en]

    ADH-A from Rhodococcus ruber DSM 44541 catalyzes the oxidation of (S)-1-phenylethanol 3000-fold more efficiently as compared with the 2-hydroxylated derivative (R)-phenylethane-1,2-diol. The enzyme is also highly selective for sec-alcohols with comparably low activities with the corresponding primary alcohols. When challenged with a substrate containing two secondary alcohols, such as 1-phenylpropane-(1R,2S)-diol, ADH-A favors the oxidation of the benzylic carbon of this alcohol. The catalytic efficiency, however, is modest in comparison to the activity with (S)-1-phenylethanol. To investigate the structural requirements for improved oxidation of vicinal diols, we conducted iterative saturation mutagenesis combined with activity screening. A first-generation variant, B1 (Y54G, L119Y) displays a 2-fold higher kcat value with 1-phenylpropane-(1R,2S)-diol and a shift in the cooperative behavior in alcohol binding, from negative in the wild type, to positive in B1, suggesting a shift from a less active enzyme form (T) in the wild type to a more active form (R) in the B1 variant. Also, the regiopreference changed to favor oxidation of C-2. A second-generation variant, B1F4 (F43T, Y54G, L119Y, F282W), shows further improvement in the turnover and regioselectivity in oxidation of 1-phenylpropane-(1R,2S)-diol. The crystal structures of the B1 and B1F4 variants describe the structural alterations to the active site, the most significant of which is a repositioning of a Tyr side-chain located distal to the coenzyme and the catalytic zinc ion. The links between the changes in structures and stereoselectivities are rationalized by molecular dynamics simulations of substrate binding at the respective active sites.

    Keywords: alcohol dehydrogenase; alcohol oxidation; biocatalysis; crystal structure; directed evolution; enzyme engineering; molecular dynamics simulations; stereoselectivity

  • 13.
    Mydy, Lisa S.
    et al.
    SUNY Buffalo, Dept Struct Biol, Buffalo, NY 14203 USA.
    Cristobal, Judith R.
    SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA.
    Katigbak, Roberto D.
    SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA.
    Bauer, Paul
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology.
    Reyes, Archie C.
    SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA.
    Kamerlin, Shina Caroline Lynn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Richard, John P.
    SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA.
    Gulick, Andrew M.
    SUNY Buffalo, Dept Struct Biol, Buffalo, NY 14203 USA.
    Human Glycerol 3-Phosphate Dehydrogenase: X-ray Crystal Structures That Guide the Interpretation of Mutagenesis Studies2019In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 58, no 8, p. 1061-1073Article in journal (Refereed)
    Abstract [en]

    Human liver glycerol 3-phosphate dehydrogenase (hlGPDH) catalyzes the reduction of dihydroxyacetone phosphate (DHAP) to form glycerol 3-phosphate, using the binding energy associated with the nonreacting phosphodianion of the substrate to properly orient the enzyme-substrate complex within the active site. Herein, we report the crystal structures for unliganded, binary E.NAD, and ternary E.NAD.DHAP complexes of wild type hlGPDH, illustrating a new position of DHAP, and probe the kinetics of multiple mutant enzymes with natural and truncated substrates. Mutation of Lys120, which is positioned to donate a proton to the carbonyl of DHAP, results in similar increases in the activation barrier to hlGPDH-catlyzed reduction of DHAP and to phosphite dianion-activated reduction of glycolaldehyde, illustrating that these transition states show similar interactions with the cationic K120 side chain. The K120A mutation results in a 5.3 kcal/mol transition state destabilization, and 3.0 kcal/mol of the lost transition state stabilization is rescued by 1.0 M ethylammonium cation. The 6.5 kcal/mol increase in the activation barrier observed for the D260G mutant hlGPDH-catalyzed reaction represents a 3.5 kcal/mol weakening of transition state stabilization by the K120A side chain and a 3.0 kcal/mol weakening of the interactions with other residues. The interactions, at the enzyme active site, between the K120 side chain and the Q295 and R269 side chains were likewise examined by double-mutant analyses. These results provide strong evidence that the enzyme rate acceleration is due mainly or exclusively to transition state stabilization by electrostatic interactions with polar amino acid side chains.

  • 14.
    Repic, Matej
    et al.
    Laboratory for Biocomputing and Bioinformatics, National Institute of Chemistry, Ljubljana, Slovenia.
    Vianello, Robert
    Quantum Organic Chemistry Group, Ruđer Bošković Institute, Zagreb, Croatia.
    Purg, Miha
    Laboratory for Biocomputing and Bioinformatics, National Institute of Chemistry, Ljubljana, Slovenia.
    Duarte, Fernanda
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Kamerlin, Lynn Shina Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Mavri, Janez
    Laboratory for Biocomputing and Bioinformatics, National Institute of Chemistry, Ljubljana, Slovenia.
    Empirical valence bond simulations of the hydride transfer step in the monoamine oxidase B catalyzed metabolism of dopamine2014In: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 82, no 12, p. 3347-3355Article in journal (Refereed)
    Abstract [en]

    Monoamine oxidases (MAOs) A and B are flavoenzymes responsible for the metabolism of biogenic amines such as dopamine, serotonin and noradrenaline. In this work, we present a comprehensive study of the rate-limiting step of dopamine degradation by MAO B, which consists in the hydride transfer from the methylene group of the substrate to the flavin moiety of the FAD prosthetic group. This article builds on our previous quantum chemical study of the same reaction using a cluster model (Vianello et al., Eur J Org Chem 2012; 7057), but now considering the full dimensionality of the hydrated enzyme with extensive configurational sampling. We show that MAO B is specifically tuned to catalyze the hydride transfer step from the substrate to the flavin moiety of the FAD prosthetic group and that it lowers the activation barrier by 12.3 kcal mol(-1) compared to the same reaction in aqueous solution, a rate enhancement of more than nine orders of magnitude. Taking into account the deprotonation of the substrate prior to the hydride transfer reaction, the activation barrier in the enzyme is calculated to be 16.1 kcal mol(-1), in excellent agreement with the experimental value of 16.5 kcal mol(-1). Additionally, we demonstrate that the protonation state of the active site residue Lys296 does not have an influence on the hydride transfer reaction.

  • 15.
    Satpati, Priyadarshi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Bauer, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Åqvist, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Energetic Tuning by tRNA Modifications Ensures Correct Decoding of Isoleucine and Methionine on the Ribosome2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 33, p. 10271-10275Article in journal (Refereed)
    Abstract [en]

    Chemical modifications of tRNAs are critical for accurate translation of the genetic code on the ribosome. The discrimination between isoleucine (AUA) and methionine (AUG) codons depends on such modifications of the wobble position in isoleucine tRNA anticodon loops, in all kingdoms of life. Bacteria and archaea employ functionally similar lysine- and agmatine-conjugated cytidine derivatives to ensure decoding fidelity, but the thermodynamics underlying codon discrimination remains unknown. Here, we report structure-based computer simulations that quantitatively reveal the energetics of this decoding strategy in archaea. The results further show that the agmatidine modification confers tRNA specificity primarily by desolvation of the incorrect codon in the non-cognate complex. Tautomerism is found to play no significant role in this decoding system as the usual amino form of the modified tRNA is by far the most stable.

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