5ngk

The endo-beta1,6-glucanase BT3312

spinqualitylabelsall models 5ngk, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ngk is a 3 chain structure with sequence from Bacteroides thetaiotaomicron. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8A2J3_BACTN Publication Abstract from PubMed Glycans are major nutrients available to the human gut microbiota (HGM). The Bacteroides are generalist glycan degraders and this function is mediated largely by polysaccharide utilization loci (PULs). The genomes of several Bacteroides species contain a PUL, PUL1,6-beta;-glucan, that was predicted to target mixed linked plant 1,3;1,4-beta-glucans. To test this hypothesis we characterized the proteins encoded by this locus in Bacteroides thetaiotaomicron, a member of the HGM. We show here that PUL1,6-beta-glucan does not orchestrate the degradation of a plant polysaccharide but targets a fungal cell wall glycan, 1,6-beta-glucan, which is a growth substrate for the bacterium. The locus is upregulated by 1,6-beta-glucan, and encodes two enzymes, a surface endo-1,6-beta-glucanase, BT3312, and a periplasmic beta-glucosidase that targets primarily 1,6-beta-glucans. The non-catalytic proteins encoded by PUL1,6-beta-glucan target 1,6-beta-glucans and comprise a surface glycan binding protein and a SusD homologue that delivers glycans to the outer membrane transporter. We identified the central role of the endo-1,6-beta-glucanase in 1,6-beta-glucan depolymerization by deleting bt3312, which prevented the growth of B. thetaiotaomicron on 1,6-beta-glucan. The crystal structure of BT3312 in complex with beta-glucosyl-1,6-deoxynojirimycin, revealed a TIM barrel catalytic domain that contains a deep substrate binding cleft tailored to accommodate the hook-like structure adopted by 1,6-beta-glucan. Specificity is driven by the complementarity of the enzyme active site cleft and the conformation of the substrate. We also noted that PUL1,6-beta-glucan is syntenic to many PULs from other Bacteroidetes suggesting that utilization of yeast and fungal cell wall 1,6-beta-glucans is a widespread adaptation within the human microbiota. A Bacteroidetes locus dedicated to fungal 1,6-beta-glucan degradation: unique substrate conformation drives specificity of the key endo-1,6-beta-glucanase.,Temple MJ, Cuskin F, Basle A, Hickey N, Speciale G, Williams SJ, Gilbert HJ, Lowe EC J Biol Chem. 2017 May 1. pii: jbc.M117.787606. doi: 10.1074/jbc.M117.787606. PMID:28461332 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Glucanase 3D structures

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