Structure and catalysis of acylaminoacyl peptidase: closed and open subunits of a dimer oligopeptidase.

ABSTRACT: Acylaminoacyl peptidase from Aeropyrum pernix is a homodimer that belongs to the prolyl oligopeptidase family. The monomer subunit is composed of one hydrolase and one propeller domain. Previous crystal structure determinations revealed that the propeller domain obstructed the access of substrate to the active site of both subunits. Here we investigated the structure and the kinetics of two mutant enzymes in which the aspartic acid of the catalytic triad was changed to alanine or asparagine. Using different substrates, we have determined the pH dependence of specificity rate constants, the rate-limiting step of catalysis, and the binding of substrates and inhibitors. The catalysis considerably depended both on the kind of mutation and on the nature of the substrate. The results were interp

SUBMITTER: Harmat V 

PROVIDER: S-EPMC3023495 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature