6ptd | pdb_00006ptd

PHOSPHATIDYLINOSITOL-SPECIFIC PHOSPHOLIPASE C MUTANT H32L

spinqualitylabelsall models 6ptd, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6ptd is a 1 chain structure with sequence from Atcc 14579. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: PI-PLC GENE (ATCC 14579) Activity: Phosphatidylinositol diacylglycerol-lyase, with EC number 4.6.1.13 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [PLC_BACCE] Cleaves glycosylphosphatidylinositol (GPI) and phosphatidylinositol (PI) anchors but not PI phosphates. 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 The role of amino acid residues located in the active site pocket of phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus cereus[Heinz, D. W., Ryan, M., Bullock, T., & Griffith, O. H. (1995) EMBO J. 14, 3855-3863] was investigated by site-directed mutagenesis, kinetics, and crystal structure analysis. Twelve residues involved in catalysis and substrate binding (His32, Arg69, His82, Gly83, Lys115, Glu117, Arg163, Trp178, Asp180, Asp198, Tyr200, and Asp274) were individually replaced by 1-3 other amino acids, resulting in a total number of 21 mutants. Replacements in the mutants H32A, H32L, R69A, R69E, R69K, H82A, H82L, E117K, R163I, D198A, D198E, D198S, Y200S, and D274S caused essentially complete inactivation of the enzyme. The remaining mutants (G83S, K115E, R163K, W178Y, D180S, Y200F, and D274N) exhibited reduced activities up to 57% when compared with wild-type PI-PLC. Crystal structures determined at a resolution ranging from 2.0 to 2.7 A for six mutants (H32A, H32L, R163K, D198E, D274N, and D274S) showed that significant changes were confined to the site of the respective mutation without perturbation of the rest of the structure. Only in mutant D198E do the side chains of two neighboring arginine residues move across the inositol binding pocket toward the newly introduced glutamic acid. An analysis of these structure-function relationships provides new insight into the catalytic mechanism, and suggests a molecular explanation of some of the substrate stereospecificity and inhibitor binding data available for this enzyme. Probing the roles of active site residues in phosphatidylinositol-specific phospholipase C from Bacillus cereus by site-directed mutagenesis.,Gassler CS, Ryan M, Liu T, Griffith OH, Heinz DW Biochemistry. 1997 Oct 21;36(42):12802-13. PMID:9335537 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phospholipase C

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