Amino acid residue 247 in canine sulphotransferase SULT1D1: a new determinant of substrate selectivity.
2004 (English)In: Biochemical Journal, Vol. 378, 687–692- p.Article in journal (Refereed) Published
The SULT (sulphotransferase) family plays a critical role in the detoxification and activation of endogenous and exogenous compounds as well as in the regulation of steroid hormone actions and neurotransmitter functions. The structure–activity relationships of the human SULTs have been investigated with focus on the amino acid 146 in hSULT1A3 and its impact on dopamine/PNP (p-nitrophenol) specificity. In the present study, we have generated canine SULT1D1 (cSULT1D1) variants with mutations at amino acid residues in the substrate-binding pocket [A146E (Ala-146Glu), A146D, A146Q, I86D or D247L]. These mutation sites were chosen with regard to their possible contribution to the marked dopamine/PNP preference of cSULT1D1. After characterization, we found that the overall sulphation efficiencies for the cSULT1D1 A146 and the I86 mutants were strongly decreased for both substrates compared with wild-type cSULT1D1 but the substrate preference was unchanged. In contrast, the D247L mutant was found to be more than 21-fold better at sulphating PNP (120-fold decrease in Km value) but 54-fold less efficient in sulphating dopamine (8-fold increase in Km value) and the preference was switched from dopamine to PNP, indicating the importance of this amino acid in the dopamine/PNP preference in cSULT1D1. Our results show that Asp-247 has a pronounced effect on the substrate specificity of cSULT1D1 and thus we have identified a previously unrecognized contributor to active-site selectivity.
Place, publisher, year, edition, pages
2004. Vol. 378, 687–692- p.
IdentifiersURN: urn:nbn:se:uu:diva-72723DOI: doi:10.1042/BJ20031470PubMedID: 14614767OAI: oai:DiVA.org:uu-72723DiVA: diva2:100634