Factors modulating conformational equilibria in large modular proteins: a case study with cobalamin-dependent methionine synthase.

ABSTRACT: In the course of catalysis or signaling, large multimodular proteins often undergo conformational changes that reposition the modules with respect to one another. The mechanisms that direct the reorganization of modules in these proteins are of considerable importance, but distinguishing alternate conformations is a challenge. Cobalamin-dependent methionine synthase (MetH) is a 136-kDa multimodular enzyme with a cobalamin chromophore; the color of the cobalamin reflects the conformation of the protein. The enzyme contains four modules and catalyzes three different methyl transfer reactions that require different arrangements of these modules. Two of these methyl transfer reactions occur during turnover, when homocysteine is converted to methionine by using a methyl group derived from methy

SUBMITTER: Bandarian V 

PROVIDER: S-EPMC166199 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature