The last step in cephalosporin C formation revealed: Crystal Structures of Deacetylcephalosporin C Acetyltransferase from Acremonium chrysogenum in Complexes with Reaction Intermediates
2008 (English)In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 377, no 3, 935-944 p.Article in journal (Refereed) Published
Deacetylcephalosporin C acetyltransferase (DAC-AT) catalyses the last step in the biosynthesis of cephalosporin C, a broad-spectrum beta-lactam antibiotic of large clinical importance. The acetyl transfer step has been suggested to be limiting for cephalosporin C biosynthesis, but has so far escaped detailed structural analysis. We present here the crystal structures of DAC-AT in complexes with reaction intermediates, providing crystallographic snapshots of the reaction mechanism. The enzyme is found to belong to the alpha/beta hydrolase class of acetyltransferases, and the structures support previous observations of a double displacement mechanism for the acetyl transfer reaction in other members of this class of enzymes. The structures of DAC-AT reported here provide evidence of a stable acyl - enzyme complex, thus underpinning a mechanism involving acetylation of a catalytic serine residue by acetyl coenzyme A, followed by transfer of the acetyl group to deacetylcephalosporin C through a suggested tetrahedral transition state.
Place, publisher, year, edition, pages
2008. Vol. 377, no 3, 935-944 p.
cephalosporin C, beta-lactam antibiotic biosynthesis, Acremonium chrysogenum, X-ray crystallography, acetyl transferase
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:uu:diva-96606DOI: 10.1016/j.jmb.2008.01.047ISI: 000255374200030PubMedID: 18279889OAI: oai:DiVA.org:uu-96606DiVA: diva2:171240