P450cam visits an open conformation in the absence of substrate.

ABSTRACT: P450cam from Pseudomonas putida is the best characterized member of the vast family of cytochrome P450s, and it has long been believed to have a more rigid and closed active site relative to other P450s. Here we report X-ray structures of P450cam crystallized in the absence of substrate and at high and low [K(+)]. The camphor-free structures are observed in a distinct open conformation characterized by a water-filled channel created by the retraction of the F and G helices, disorder of the B' helix, and loss of the K(+) binding site. Crystallization in the presence of K(+) alone does not alter the open conformation, while crystallization with camphor alone is sufficient for closure of the channel. Soaking crystals of the open conformation in excess camphor does not promote camphor binding

SUBMITTER: Lee YT 

PROVIDER: S-EPMC2860182 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature