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Publication Abstract from PubMed

The first crystal structure of Uhgb_MP, a beta-1,4-mannopyranosyl-chitobiose phosphorylase belonging to the GH130 family which is involved in N-glycan degradation by human gut bacteria, was solved at 1.85 A resolution in the apo form and in complex with mannose and N-acetylglucosamine. SAXS and crystal structure analysis revealed a hexameric structure, a specific feature of GH130 enzymes among other glycoside phosphorylases. Mapping of the -1 and +1 subsites in the presence of phosphate confirmed the conserved Asp104 as the general acid/base catalytic residue, which is in agreement with a single-step reaction mechanism involving Man O3 assistance for proton transfer. Analysis of this structure, the first to be solved for a member of the GH130_2 subfamily, revealed Met67, Phe203 and the Gly121-Pro125 loop as the main determinants of the specificity of Uhgb_MP and its homologues towards the N-glycan core oligosaccharides and mannan, and the molecular bases of the key role played by GH130 enzymes in the catabolism of dietary fibre and host glycans.

Structural bases for N-glycan processing by mannoside phosphorylase.,Ladeveze S, Cioci G, Roblin P, Mourey L, Tranier S, Potocki-Veronese G Acta Crystallogr D Biol Crystallogr. 2015 Jun;71(Pt 6):1335-46. doi:, 10.1107/S1399004715006604. Epub 2015 May 14. PMID:26057673^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.