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1scn
From Proteopedia
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(New page: 200px<br /><applet load="1scn" size="450" color="white" frame="true" align="right" spinBox="true" caption="1scn, resolution 1.9Å" /> '''INACTIVATION OF SUBTI...)
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Revision as of 00:09, 21 November 2007
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INACTIVATION OF SUBTILISIN CARLSBERG BY N-(TERT-BUTOXYCARBONYL-ALANYL-PROLYL-PHENYLALANYL)-O-BENZOYL HYDROXYLAMINE: FORMATION OF COVALENT ENZYME-INHIBITOR LINKAGE IN THE FORM OF A CARBAMATE DERIVATIVE
Overview
The mechanism of inactivation of serine proteases by, N-peptidyl-O-aroylhydroxylamines was studied by X-ray crystallography., Cocrystals of subtilisin Carlsberg inactivated with, N-((tert-butoxycarbonyl)alanylprolylphenylalanyl)-O-nitrobenzoy, lhydroxylamine were grown, and diffraction data to 1.8-A resolution were, obtained. The resulting electron density maps clearly reveal that the, gamma-oxygen of the catalytic serine forms a carbamate derivative with the, inhibitor. The peptide part of the inhibitor does not form the usual, antiparallel beta-sheet in the P binding cleft but protrudes out of the, active site and is stabilized by a network of water molecules. These, results, combined with kinetic characterization reported previously, [Demuth, H.-U., Schoenlein, C., & Barth, A. (1989b) Biochim. Biophys. Acta, 996, 19-22; Schmidt, C., Schmidt, R., & Demuth, H.-U. (1990) Peptides, (Giralt, E., & Andreu, D., Eds.) ESCOM Science Publishers B.V., Amsterdam], support the existence of at least one intermediate between the formation, of the Michaelis complex and the final product. We suggest a mechanism for, the inactivation of subtilisin Carlsberg by, N-((tert-butoxycarbonyl)alanylprolylphenylalanyl)-O-benzoylhydr oxylamine, whereby a negatively charged Michaelis complex undergoes a Lossen, rearrangement giving rise to an isocyanate intermediate that reacts with, the side chain of the active site serine.
About this Structure
1SCN is a Single protein structure of sequence from [1] with CA and NA as ligands. Active as Subtilisin, with EC number 3.4.21.62 Full crystallographic information is available from OCA.
Reference
Inactivation of subtilisin Carlsberg by N-((tert-butoxycarbonyl)alanylprolylphenylalanyl)-O-benzoylhydroxyl- amine: formation of a covalent enzyme-inhibitor linkage in the form of a carbamate derivative., Steinmetz AC, Demuth HU, Ringe D, Biochemistry. 1994 Aug 30;33(34):10535-44. PMID:8068694
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