The critical role of substrate-protein hydrogen bonding in the control of regioselective hydroxylation in p450cin.

ABSTRACT: Cytochrome P450cin (CYP176A1) is a bacterial P450 isolated from Citrobacter braakii that catalyzes the hydroxylation of cineole to (S)-6beta-hydroxycineole. This initiates the biodegradation of cineole, enabling C. braakii to live on cineole as its sole source of carbon and energy. P450cin lacks the almost universally conserved threonine residue believed to be involved in dioxygen activation and instead contains an asparagine at this position (Asn-242). To investigate the role of Asn-242 in P450cin catalysis, it was converted to alanine, and the resultant mutant was characterized. The characteristic CO-bound spectrum and spectrally determined K(D) for substrate binding were unchanged in the mutant. The x-ray crystal structures of the substrate-free and -bound N242A mutant were determined a

SUBMITTER: Meharenna YT 

PROVIDER: S-EPMC2447660 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature