The F209L mutation alters specificity of P450coh from coumarin 7-hydroxylation to 15 alpha-hydroxylation of 11-deoxysteroids such as testosterone and 11-deoxycorticosterone. Neither the wild-type nor F209L exhibits activity toward 11 beta-hydroxysteroids including corticosterone. Mutation of Phe-209 to Asn, however, confers on mutant F209N a high corticosterone 15 alpha-hydroxylase activity. F209V also exhibits low corticosterone 15 alpha-hydroxylase activity; Km and Vmax are 10-fold higher and lower, respectively, than for F209N. The results are consistent with the hypothesis that direct interaction of Asn-209 with 11OH is responsible for high corticosterone 15 alpha-hydroxylase activity. To support this hypothesis, a possible steroid-binding orientation is modeled in the substrate pocket of P450cam. Our weighted homology and constrained alignments map residue 209 of P450coh to Met-184 and Met-191 of P450cam. Energy minimization of corticosterone in the substrate pocket results in the 11OH of the steroid directed toward Met-184 (7 A) and Met-191 (16 A), and in C15 located near the sixth axial position of the heme. The steroid-binding model suggests that the P450cam's substrate pocket may be conserved in the mammalian P450 and can accommodate a steroid molecule, and that residue 209 appears to be located at the critical site that determines the steroid-substrate specificity of a P450 depending on the type of group at the 11-position of steroid molecule.
Engineering mouse P450coh to a novel corticosterone 15 alpha-hydroxylase and modeling steroid-binding orientation in the substrate pocket.
M. Iwasaki,T. Darden,L. Pedersen,D. G. Davis,R. Juvonen,T. Sueyoshi,M. Negishi
Published 1993 in Journal of Biological Chemistry
ABSTRACT
PUBLICATION RECORD
- Publication year
1993
- Venue
Journal of Biological Chemistry
- Publication date
1993-01-15
- Fields of study
Biology, Medicine, Chemistry, Engineering
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
- No claims are published for this paper.
CONCEPTS
- No concepts are published for this paper.
REFERENCES
Showing 1-13 of 13 references · Page 1 of 1
CITED BY
Showing 1-68 of 68 citing papers · Page 1 of 1