This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
2gam
From Proteopedia
|
X-ray crystal structure of murine leukocyte-type Core 2 b1,6-N-acetylglucosaminyltransferase (C2GnT-L) in complex with Galb1,3GalNAc
Overview
Leukocyte type core 2 beta1,6-N-acetylglucosaminyltransferase (C2GnT-L) is, a key enzyme in the biosynthesis of branched O-glycans. It is an, inverting, metal ion-independent family 14 glycosyltransferase that, catalyzes the formation of the core 2 O-glycan, (Galbeta1-3[GlcNAcbeta1-6]GalNAc-O-Ser/Thr) from its donor and acceptor, substrates, UDP-GlcNAc and the core 1 O-glycan, (Galbeta1-3GalNAc-O-Ser/Thr), respectively. Reported here are the x-ray, crystal structures of murine C2GnT-L in the absence and presence of the, acceptor substrate Galbeta1-3GalNAc at 2.0 and 2.7A resolution, respectively. C2GnT-L was found to possess the GT-A fold; however, it, lacks the characteristic metal ion binding DXD motif. The Galbeta1-3GalNAc, complex defines the determinants of acceptor substrate binding and shows, that Glu-320 corresponds to the structurally conserved catalytic base, found in other inverting GT-A fold glycosyltransferases. Comparison of the, C2GnT-L structure with that of other GT-A fold glycosyltransferases, further suggests that Arg-378 and Lys-401 serve to electrostatically, stabilize the nucleoside diphosphate leaving group, a role normally played, by metal ion in GT-A structures. The use of basic amino acid side chains, in this way is strikingly similar to that seen in a number of metal, ion-independent GT-B fold glycosyltransferases and suggests a convergence, of catalytic mechanism shared by both GT-A and GT-B fold, glycosyltransferases.
About this Structure
2GAM is a Single protein structure of sequence from Mus musculus. Active as Beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-N- acetylglucosaminyltransferase, with EC number 2.4.1.102 Full crystallographic information is available from OCA.
Reference
X-ray crystal structure of leukocyte type core 2 beta1,6-N-acetylglucosaminyltransferase. Evidence for a convergence of metal ion-independent glycosyltransferase mechanism., Pak JE, Arnoux P, Zhou S, Sivarajah P, Satkunarajah M, Xing X, Rini JM, J Biol Chem. 2006 Sep 8;281(36):26693-701. Epub 2006 Jul 7. PMID:16829524
Page seeded by OCA on Wed Nov 21 11:04:59 2007
