1klt | pdb_00001klt

CRYSTAL STRUCTURE OF PMSF-TREATED HUMAN CHYMASE AT 1.9 ANGSTROMS RESOLUTION

spinqualitylabelsall models 1klt, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1klt is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: PMS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CMA1_HUMAN Major secreted protease of mast cells with suspected roles in vasoactive peptide generation, extracellular matrix degradation, and regulation of gland secretion. 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 X-ray crystal structure of human chymase has been determined to 1.9 A resolution using molecular replacement methods. This first structure of human chymase is present as the Ser 195 ester of alpha-toluenesulfonic acid. The refined structure (Rcryst = 0.183) shows that the inhibitor phenyl moiety lies at the top of the major specificity pocket, S1, while the sulfur is covalently linked to Ser 195-O gamma. The sulfonyl oxygens interact with the oxyanion hole and with His 57-N delta 1. The presence of the inhibitor disturbs the usual gauche position of His 57 and forces it to the trans conformer. Though the primary binding pockets are similarly specific in chymase and chymotrypsin, examination of the extended substrate binding sites reveals the structural basis for chymase's greater discrimination in choosing substrates. The larger 30s loop and its proximity to the active site indicates that it contacts substrate residues C-terminal to the scissile bond. Modeling of substrate at the chymase active site suggests that binding energy may be gained by three main-chain hydrogen bonds provided by substrate residues P2' and P4' and that discriminating interactions with substrate side chains are also likely. The presence of Lys 40 in S1' of human chymase explains its preference for Asp/Glu at P1'. Moreover, the cationic nature of S1' provides a structural basis for human chymase's poor catalytic efficiency when angiotensin II is the substrate. Crystal structure of phenylmethanesulfonyl fluoride-treated human chymase at 1.9 A.,McGrath ME, Mirzadegan T, Schmidt BF Biochemistry. 1997 Nov 25;36(47):14318-24. PMID:9400368 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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