5a8p

Crystal structure beta-glucanase SdGluc5_26A from Saccharophagus degradans in complex with tetrasaccharide B

spinqualitylabelsall models 5a8p, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5a8p is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BGC, CL, GOL, MG, PGE, SO4 Related: 5a8m, 5a8n, 5a8o, 5a8q, 5a94, 5a95 Activity: Licheninase, with EC number 3.2.1.73 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Publication Abstract from PubMed In the CAZy database, glycoside hydrolase family 5 (GH5) is a large family with more than 6,000 sequences. Among the 51 described GH5 subfamilies, subfamily GH5_26 contains members that display either endo- beta(1,4)-glucanase or beta(1,3;1,4)-glucanase activities. In this study, we focused on the GH5_26 enzyme from Saccharophagus degradans (SdGluc5_26A) a marine bacterium known for its capacity to degrade a wide diversity of complex polysaccharides. SdGluc5_26A displays lichenase activity towards beta(1,3;1,4)-glucans with a side cellobiohydrolase activity towards beta(1,4)-glucans. The 3D structure of SdGluc5_26A adopts a stable trimeric quaternary structure observable also in solution. The N-terminal region of SdGluc5_26A protrudes into the active site of an adjacent monomer. To understand whether this occupation of the active site could influence its activity, we conducted a comprehensive enzymatic characterization of SdGluc5_26A and of a mutant truncated at the N-terminus. Ligand complex structures and kinetic analyses reveal that the N-terminus governs the substrate specificity of SdGluc5_26A. Its deletion opens the enzyme cleft at the -3 subsite and turns the enzyme into an endo-beta(1,4)-glucanase. This study demonstrates that experimental approaches can reveal structure-function relationships out of reach of current bioinformatic predictions. the quaternary structure of a glycoside hydrolase dictates specificity towards beta-glucans.,Lafond M, Sulzenbacher G, Freyd T, Henrissat B, Berrin JG, Garron ML J Biol Chem. 2016 Jan 11. pii: jbc.M115.695999. PMID:26755730 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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