1z8p
Ferrous dioxygen complex of the A245S cytochrome P450eryF
Structural highlights
FunctionCPXJ_SACEN Catalyzes the NADPH-dependent conversion of 6-deoxyerythronolide B (6-DEB) to erythronolide B (EB) by the insertion of an oxygen at the 6S position of 6-DEB. Requires the participation of a ferredoxin and a ferredoxin reductase for the transfer of electrons from NADPH to the monooxygenase.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCytochrome P450eryF (CYP107A) from Saccaropolyspora ertherea catalyzes the hydroxylation of 6-deoxyerythronolide B, one of the early steps in the biosynthesis of erythromycin. P450eryF has an alanine rather than the conserved threonine that participates in the activation of dioxygen (O(2)) in most other P450s. The initial structure of P450eryF (Cupp-Vickery, J. R., Han, O., Hutchinson, C. R., and Poulos, T. L. (1996) Nat. Struct. Biol. 3, 632-637) suggests that the substrate 5-OH replaces the missing threonine OH group and holds a key active site water molecule in position to donate protons to the iron-linked dioxygen, a critical step for the monooxygenase reaction. To probe the proton delivery system in P450eryF, we have solved crystal structures of ferrous wild-type and mutant (Fe(2+)) dioxygen-bound complexes. The catalytic water molecule that was postulated to provide protons to dioxygen is absent, although the substrate 5-OH group donates a hydrogen bond to the iron-linked dioxygen. The hydrogen bond network observed in the wild-type ferrous dioxygen complex, water 63-Glu(360)-Ser(246)-water 53-Ala(241) carbonyl in the I-helix cleft, is proposed as the proton transfer pathway. Consistent with this view, the hydrogen bond network in the O(2).A245S and O(2) .A245T mutants, which have decreased or no enzyme activity, was perturbed or disrupted, respectively. The mutant Thr(245) side chain also perturbs the hydrogen bond between the substrate 5-OH and dioxygen ligand. Contrary to the previously proposed mechanism, these results support the direct involvement of the substrate in O(2) activation but raise questions on the role water plays as a direct proton donor to the iron-linked dioxygen. Crystal structures of the ferrous dioxygen complex of wild-type cytochrome P450eryF and its mutants, A245S and A245T: investigation of the proton transfer system in P450eryF.,Nagano S, Cupp-Vickery JR, Poulos TL J Biol Chem. 2005 Jun 10;280(23):22102-7. Epub 2005 Apr 11. PMID:15824115[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||
