3VSB: Subtilisin Carlsberg D-Naphthyl-1-Acetamido Boronic Acid Inhibitor Complex

Citation:
Abstract
In 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.
PDB ID: 3VSBDownload
MMDB ID: 58383
PDB Deposition Date: 1997/9/25
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2.6  Å
Source Organism:
Similar Structures:
Biological Unit for 3VSB: monomeric; determined by author
Molecular Components in 3VSB
Label Count Molecule
Protein (1 molecule)
1
Subtilisin Carlsberg, Type Viii
Molecule annotation
Chemicals (2 molecules)
1
2
* Click molecule labels to explore molecular sequence information.

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