Alpha-lytic protease can exist in two separately stable conformations with different His57 mobilities and catalytic activities.

ABSTRACT: alpha-Lytic protease is a bacterial serine protease widely studied as a model system of enzyme catalysis. Here we report that lyophilization induces a structural change in the enzyme that is not reversed by redissolution in water. The structural change reduces the mobility of the active-site histidine residue and the catalytic activity of the enzyme. The application of mild pressure to solutions of the altered enzyme reverses the lyophilization-induced structural change and restores the mobility of the histidine residue and the enzyme's catalytic activity. This effect of lyophilization permits a unique opportunity for investigating the relationship between histidine ring dynamics and catalytic activity. The results demonstrate that His57 in resting enzymes is more mobile than previously th

SUBMITTER: Haddad KC 

PROVIDER: S-EPMC545854 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature