7TLN

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

Replaces:  6TLN

Summary for 7TLN

• Entry DOI: 10.2210/pdb7tln/pdb
• Descriptor: THERMOLYSIN, CALCIUM ION, ZINC ION, ... (5 entities in total)
• Functional Keywords: hydrolase (metalloproteinase)
• Biological source: Bacillus thermoproteolyticus
• Cellular location: Secreted: P00800
• Total number of polymer chains: 1
• Total formula weight: 34791.26

Authors

Matthews, B.W.,Holmes, M.A.,Tronrud, D.E. (deposition date: 1983-01-27, release date: 1983-03-09, Last modification date: 2024-10-23)

Primary citation

Holmes, M.A.,Tronrud, D.E.,Matthews, B.W.
Structural analysis of the inhibition of thermolysin by an active-site-directed irreversible inhibitor.
Biochemistry, 22:236-240, 1983

PubMed Abstract: 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.

PubMed: 6830761
DOI: 10.1021/bi00270a034

Experimental method

X-RAY DIFFRACTION (2.3 Å)