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Substrate‐Guided Front‐Face Reaction Revealed by Combined Structural Snapshots and Metadynamics for the Polypeptide N ‐Acetylgalactosaminyltransferase 2
Author(s) -
LiraNavarrete Erandi,
IglesiasFernández Javier,
Zandberg Wesley F.,
Compañón Ismael,
Kong Yun,
Corzana Francisco,
Pinto B. Mario,
Clausen Henrik,
Peregrina Jesús M.,
Vocadlo David J.,
Rovira Carme,
HurtadoGuerrero Ramon
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201402781
Subject(s) - metadynamics , substrate (aquarium) , chemistry , glycosyl , substituent , glycosyltransferase , electron transfer , substrate specificity , stereochemistry , qm/mm , enzyme , computational chemistry , molecular dynamics , biochemistry , biology , photochemistry , ecology
The retaining glycosyltransferase GalNAc‐T2 is a member of a large family of human polypeptide GalNAc‐transferases that is responsible for the post‐translational modification of many cell‐surface proteins. By the use of combined structural and computational approaches, we provide the first set of structural snapshots of the enzyme during the catalytic cycle and combine these with quantum‐mechanics/molecular‐mechanics (QM/MM) metadynamics to unravel the catalytic mechanism of this retaining enzyme at the atomic‐electronic level of detail. Our study provides a detailed structural rationale for an ordered bi–bi kinetic mechanism and reveals critical aspects of substrate recognition, which dictate the specificity for acceptor Thr versus Ser residues and enforce a front‐face S N i‐type reaction in which the substrate N ‐acetyl sugar substituent coordinates efficient glycosyl transfer.