| First Author | Negishi M | Year | 1992 |
| Journal | J Steroid Biochem Mol Biol | Volume | 43 |
| Issue | 8 | Pages | 1031-6 |
| PubMed ID | 22217847 | Mgi Jnum | J:4734 |
| Mgi Id | MGI:53217 | Doi | 10.1016/0960-0760(92)90330-L |
| Citation | Negishi M, et al. (1992) Alteration of the substrate specificity of mouse 2A P450s by the identity of residue-209: steroid-binding site and orientation. J Steroid Biochem Mol Biol 43(8):1031-6 |
| abstractText | Mouse steroid 7alpha- and 15alpha-hydroxylases (P450c7 and P450c15) and coumarin 7-hydroxylase (P450coh) are structurally similar. To study the structural basis of the substrate specificities of these enzymes, we constructed a series of the mutant P450s, expressed in COS-1 and yeast cells, and studied them spectroscopically as well as enzyme-kinetically. A single amino acid mutation of residue-209 is sufficient to alter the substrate specificity of the P450s from xenobiotics to steroids and subsequently, from testosterone to corticosterone. Moreover, residue-209, when it is asparagine, appears to bind directly to the 11beta-hydroxyl of corticosterone. The mutations also after the spin equilibrium of P450 depending on the hydrophobicity and size of residue-209. We conclude, therefore, that residue-209 resides close to the 6th ligand of heme in the mouse 2A subfamily and is located at a critical site of the substrate-binding pocket. As a result, the identity of the residue-209 plays a key role in determining the substrate specificity. |
