4V28

Structure of an E333Q variant of the GH99 endo-alpha-mannanase from Bacteroides xylanisolvens in complex with Man-Man-Methylumbelliferone

Summary for 4V28

• Entry DOI: 10.2210/pdb4v28/pdb
• Related: 4V1R 4V1S 4V27
• Related PRD ID: PRD_900112
• Descriptor: GLYCOSYL HYDROLASE FAMILY 71, alpha-D-mannopyranose-(1-3)-alpha-D-mannopyranose, 7-hydroxy-4-methyl-2H-chromen-2-one, ... (6 entities in total)
• Functional Keywords: hydrolase, gh99, cazy, mannan, bacteroides, polysaccharide utilisation, enzyme-carbohydrate interaction, substrate complex
• Biological source: BACTEROIDES XYLANISOLVENS
• Total number of polymer chains: 1
• Total formula weight: 44235.95

Authors

Hakki, Z.,Bellmaine, S.,Thompson, A.J.,Speciale, G.,Davies, G.J.,Williams, S.J. (deposition date: 2014-10-07, release date: 2014-12-24, Last modification date: 2024-01-10)

Primary citation

Hakki, Z.,Thompson, A.J.,Bellmaine, S.,Speciale, G.,Davies, G.J.,Williams, S.J.
Structural and Kinetic Dissection of the Endo-Alpha-1,2-Mannanase Activity of Bacterial Gh99 Glycoside Hydrolases from Bacteroides Spp.
Chemistry, 21:1966-, 2015

PubMed Abstract: Glycoside hydrolase family 99 (GH99) was created to categorize sequence-related glycosidases possessing endo-α-mannosidase activity: the cleavage of mannosidic linkages within eukaryotic N-glycan precursors (Glc1-3 Man9 GlcNAc2 ), releasing mono-, di- and triglucosylated-mannose (Glc1-3 -1,3-Man). GH99 family members have recently been implicated in the ability of Bacteroides spp., present within the gut microbiota, to metabolize fungal cell wall α-mannans, releasing α-1,3-mannobiose by hydrolysing αMan-1,3-αMan→1,2-αMan-1,2-αMan sequences within branches off the main α-1,6-mannan backbone. We report the development of a series of substrates and inhibitors, which we use to kinetically and structurally characterise this novel endo-α-1,2-mannanase activity of bacterial GH99 enzymes from Bacteroides thetaiotaomicron and xylanisolvens. These data reveal an approximate 5 kJ mol(-1) preference for mannose-configured substrates in the -2 subsite (relative to glucose), which inspired the development of a new inhibitor, α-mannopyranosyl-1,3-isofagomine (ManIFG), the most potent (bacterial) GH99 inhibitor reported to date. X-ray structures of ManIFG or a substrate in complex with wild-type or inactive mutants, respectively, of B. xylanisolvens GH99 reveal the structural basis for binding to D-mannose- rather than D-glucose-configured substrates.

PubMed: 25487964
DOI: 10.1002/CHEM.201405539

Experimental method

X-RAY DIFFRACTION (1.2 Å)