1foa

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Template:STRUCTURE 1foa

CRYSTAL STRUCTURE OF N-ACETYLGLUCOSAMINYLTRANSFERASE I

Overview

N:-acetylglucosaminyltransferase I (GnT I) serves as the gateway from oligomannose to hybrid and complex N:-glycans and plays a critical role in mammalian development and possibly all metazoans. We have determined the X-ray crystal structure of the catalytic fragment of GnT I in the absence and presence of bound UDP-GlcNAc/Mn(2+) at 1.5 and 1.8 A resolution, respectively. The structures identify residues critical for substrate binding and catalysis and provide evidence for similarity, at the mechanistic level, to the deglycosylation step of retaining beta-glycosidases. The structuring of a 13 residue loop, resulting from UDP-GlcNAc/Mn(2+) binding, provides an explanation for the ordered sequential 'Bi Bi' kinetics shown by GnT I. Analysis reveals a domain shared with Bacillus subtilis glycosyltransferase SpsA, bovine beta-1,4-galactosyl transferase 1 and Escherichia coli N:-acetylglucosamine-1-phosphate uridyltransferase. The low sequence identity, conserved fold and related functional features shown by this domain define a superfamily whose members probably share a common ancestor. Sequence analysis and protein threading show that the domain is represented in proteins from several glycosyltransferase families.

About this Structure

1FOA is a Single protein structure of sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA.

Reference

X-ray crystal structure of rabbit N-acetylglucosaminyltransferase I: catalytic mechanism and a new protein superfamily., Unligil UM, Zhou S, Yuwaraj S, Sarkar M, Schachter H, Rini JM, EMBO J. 2000 Oct 16;19(20):5269-80. PMID:11032794 Page seeded by OCA on Fri May 2 16:34:06 2008