1vgc
GAMMA-CHYMOTRYPSIN L-PARA-CHLORO-1-ACETAMIDO BORONIC ACID INHIBITOR COMPLEX
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn order to probe the structural basis of stereoselectivity in the serine protease family, a series of enantiomeric boronic acids RCH2CH(NHCOCH3)B(OH)2 has been synthesized and kinetically characterized as transition-state analog inhibitors using alpha-chymotrypsin and subtilisin Carlsberg as model systems. When the R-substituent in this series was changed from a p-chlorophenyl to a 1-naphthyl group, alpha-chymotrypsin, but not subtilisin, reversed its usual preference for l-enantiomers and bound more tightly to the D-enantiomer [Martichonok, V., & Jones, J. B. (1996) J. Am. Chem. Soc. 118, 950-958]. The structural factors responsible for the differences in stereoselectivity between the two enzymes have been explored by X-ray crystallographic examination of subtilisin Carlsberg and gamma-chymotrypsin complexes of the L- and D-enantiomers of p-chlorophenyl and 1-naphthyl boronic acid derivatives. In both enzymes, the L-isomers of the inhibitors, which are more closely related to the natural L-amino acid substrates, form tetrahedral adducts, covalently linking the central boron atom and Ogamma of the catalytic serine. The d-isomers, however, differ in the way they interact with subtilisin or gamma-chymotrypsin. With subtilisin, both the D-p-chlorophenyl and D-1-naphthyl inhibitor complexes form covalent Ser Ogamma-to-boron bonds, but with gamma-chymotrypsin, the same inhibitors lead to novel tetrahedral adducts covalently linking both Ser195 Ogamma and His57 Nepsilon2 covalently via the boron atom. Differences in binding modes of enantiomers of 1-acetamido boronic acid based protease inhibitors: crystal structures of gamma-chymotrypsin and subtilisin Carlsberg complexes.,Stoll VS, Eger BT, Hynes RC, Martichonok V, Jones JB, Pai EF Biochemistry. 1998 Jan 13;37(2):451-62. PMID:9425066[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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