1z8o
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Ferrous dioxygen complex of the wild-type cytochrome P450eryF
OverviewOverview
Cytochrome 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.
About this StructureAbout this Structure
1Z8O is a Single protein structure of sequence from Saccharopolyspora erythraea with HEM, OXY and DEB as ligands. Full crystallographic information is available from OCA.
ReferenceReference
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
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