1bcx

MUTATIONAL AND CRYSTALLOGRAPHIC ANALYSES OF THE ACTIVE SITE RESIDUES OF THE BACILLUS CIRCULANS XYLANASE

spinqualitylabelsall models 1bcx, resolution 1.81Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1bcx is a 1 chain structure with sequence from Bacillus circulans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4, XYP Activity: Endo-1,4-beta-xylanase, with EC number 3.2.1.8 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Using site-directed mutagenesis we have investigated the catalytic residues in a xylanase from Bacillus circulans. Analysis of the mutants E78D and E172D indicated that mutations in these conserved residues do not grossly alter the structure of the enzyme and that these residues participate in the catalytic mechanism. We have now determined the crystal structure of an enzyme-substrate complex to 108 A resolution using a catalytically incompetent mutant (E172C). In addition to the catalytic residues, Glu 78 and Glu 172, we have identified 2 tyrosine residues, Tyr 69 and Tyr 80, which likely function in substrate binding, and an arginine residue, Arg 112, which plays an important role in the active site of this enzyme. On the basis of our work we would propose that Glu 78 is the nucleophile and that Glu 172 is the acid-base catalyst in the reaction. Mutational and crystallographic analyses of the active site residues of the Bacillus circulans xylanase.,Wakarchuk WW, Campbell RL, Sung WL, Davoodi J, Yaguchi M Protein Sci. 1994 Mar;3(3):467-75. PMID:8019418 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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