1eok
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(New page: 200px<br /><applet load="1eok" size="450" color="white" frame="true" align="right" spinBox="true" caption="1eok, resolution 1.80Å" /> '''CRYSTAL STRUCTURE OF...)
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Revision as of 12:03, 20 November 2007
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CRYSTAL STRUCTURE OF ENDO-BETA-N-ACETYLGLUCOSAMINIDASE F3
Overview
Endo-beta-N-acetylglucosaminidase F(3) cleaves the beta(1-4) link between, the core GlcNAc's of asparagine-linked oligosaccharides, with specificity, for biantennary and triantennary complex glycans. The crystal structures, of Endo F(3) and the complex with its reaction product, the biantennary, octasaccharide, Gal-beta(1-4)-GlcNAc-beta(1-2)-Man-alpha(1-3)[Gal-beta(1-4)-GlcNAc-be, ta(1-2)-Man-alpha(1-6)]-Man-beta(1-4)-GlcNAc, have been determined to 1.8, and 2.1 A resolution, respectively. Comparison of the structure of Endo, F(3) with that of Endo F(1), which is specific for high-mannose, oligosaccharides, reveals highly distinct folds and amino acid, compositions at the oligosaccharide recognition sites. Binding of the, oligosaccharide to the protein does not affect the protein conformation., The conformation of the oligosaccharide is similar to that seen for other, biantennary oligosaccharides, with the exception of two links: the, Gal-beta(1-4)-GlcNAc link of the alpha(1-3) branch and the, GlcNAc-beta(1-2)-Man link of the alpha(1-6) branch. Especially the latter, link is highly distorted and energetically unfavorable. Only the, reducing-end GlcNAc and two Man's of the trimannose core are in direct, contact with the protein. This is in contrast with biochemical data for, Endo F(1) that shows that activity depends on the presence and identity of, sugar residues beyond the trimannose core. The substrate specificity of, Endo F(3) is based on steric exclusion of incompatible oligosaccharides, rather than on protein-carbohydrate interactions that are unique to, complexes with biantennary or triantennary complex glycans.
About this Structure
1EOK is a Single protein structure of sequence from Elizabethkingia meningoseptica with SO4 as ligand. Active as Mannosyl-glycoprotein endo-beta-N-acetylglucosaminidase, with EC number 3.2.1.96 Full crystallographic information is available from OCA.
Reference
Structural basis for the substrate specificity of endo-beta-N-acetylglucosaminidase F(3)., Waddling CA, Plummer TH Jr, Tarentino AL, Van Roey P, Biochemistry. 2000 Jul 11;39(27):7878-85. PMID:10891067
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