7tln | pdb_00007tln

STRUCTURAL ANALYSIS OF THE INHIBITION OF THERMOLYSIN BY AN ACTIVE-SITE-DIRECTED IRREVERSIBLE INHIBITOR

spinqualitylabelsall models 7tln, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7tln is a 1 chain structure with sequence from Bacillus thermoproteolyticus. This structure supersedes the now removed PDB entry 6tln. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, INC, ZN Activity: Thermolysin, with EC number 3.4.24.27 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 The mode of binding of the irreversible thermolysin inhibitor ClCH2CO-DL-(N-OH)Leu-OCH3 [Rasnick, D., & Powers, J.C. (1978) Biochemistry 17, 4363-4369] has been determined by X-ray crystallography at a resolution of 2.3 A and the structure of the covalent complex refined to give a crystallographic residual of 17.0%. This is the first such structural study of an active-site-directed covalent complex of a zinc protease. As anticipated by Rasnick and Powers, the inhibitor alkylates Glu-143 in the thermolysin active site, and the hydroxamic acid moiety coordinates the zinc ion. The formation of the covalent complex is associated with a significant shift in a segment of the polypeptide backbone in the vicinity of the active site. This conformational adjustment appears to be necessary to relieve steric hindrance which would otherwise prevent alkylation of Glu-143. It is suggested that this steric hindrance, which occurs for thermolysin but would not be expected for carboxypeptidase A, accounts for the previously inexplicable difference in reactivity of these two metalloproteases toward N-haloacetyl amino acids. The relevance of this steric hindrance to the mechanism of catalysis is discussed. In agreement with previous results [Kester, W. R., & Matthews, B. W. (1977) Biochemistry 16, 2506-2516], it appears that steric hindrance prevents the direct attack of Glu-143 on the carbonyl carbon of an extended substrate, therefore ruling out the anhydride pathway in thermolysin-catalyzed hydrolysis of polypeptide substrates and their ester analogues. Structural analysis of the inhibition of thermolysin by an active-site-directed irreversible inhibitor.,Holmes MA, Tronrud DE, Matthews BW Biochemistry. 1983 Jan 4;22(1):236-40. PMID:6830761 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thermolysin

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