1FOA: Crystal Structure Of N-acetylglucosaminyltransferase I

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.
PDB ID: 1FOADownload
MMDB ID: 15997
PDB Deposition Date: 2000/8/26
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 1FOA: monomeric; determined by author
Molecular Components in 1FOA
Label Count Molecule
Protein (1 molecule)
Alpha-1,3-mannosyl-glycoprotein Beta-1,2-n- Acetylglucosaminyltransferase(Gene symbol: MGAT1)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB