5nr9

Publication Abstract from PubMed

Glycosyltransferases (GTs) are a key family of enzymes that catalyses the synthesis of glycosidic bonds in all living organisms. The reaction involves the transfer of a glycosyl moiety and can proceed with retention or inversion of the anomeric configuration. To date, the elucidation of the catalytic mechanism of retaining GTs is of great controversy, particularly for those enzymes containing a putative nucleophilic residue in the active site, for which a double-displacement mechanism has been suggested. Here, we report native ternary complexes of the retaining alpha1,3-Galactosyltransferase (alpha3GalT) from Bos taurus - containing such a nucleophile in the active site - in a productive mode for catalysis, in the presence of its sugar donor UDP-Gal, the acceptor substrate lactose, and the divalent cation cofactor. This new experimental evidence supports a front-side substrate-assisted SNi-type reaction for alpha3GalT, and suggests a conserved common catalytic mechanism among retaining GTs.

Structural Snapshots of the Reaction Center of Family GT6 alpha1,3-Galactosyltransferase with Native Substrates. Insights into the Catalytic Mechanism of Retaining Glycosyltransferases.,Guerin ME, Albesa-Jove D, Sainz-Polo MA, Marina A Angew Chem Int Ed Engl. 2017 Sep 28. doi: 10.1002/anie.201707922. PMID:28960760^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.