2min
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NITROGENASE MOFE PROTEIN FROM AZOTOBACTER VINELANDII, OXIDIZED STATE
OverviewOverview
The structure of the nitrogenase MoFe-protein from Azotobacter vinelandii, has been refined to 2.0 A resolution in two oxidation states. EPR studies, on the crystals indicate that the structures correspond to the, spectroscopically assigned oxidized (P(OX)/M(OX)) and the native or, dithionite-reduced (P(N)/M(N)) forms of the enzyme. Both MoFe-protein, structures are essentially identical, with the exception of the P-cluster., The MoFe-protein P-cluster in each state is found to contain eight Fe and, seven S atoms. Interconversion between the two redox states involves, movement of two Fe atoms and an exchange of protein coordination for, ligands supplied by a central S atom. In the oxidized P(OX) state, the, cluster is coordinated by the protein through six cysteine ligands, Ser-beta188 O gamma, and the backbone amide of Cys-alpha88. In the native, P(N) state, Ser-beta188 O gamma and the amide N of Cys-alpha88 no longer, coordinate the cluster due to movement of their coordinated Fe atoms, toward the central sulfur. Consequently, this central sulfur adopts a, distorted octahedral environment with six surrounding Fe atoms. A, previously described model of the P-cluster containing 8Fe-8S likely, reflects the inappropriate modeling of a single structure to a mixture of, these two P-cluster redox states. These observed redox-mediated structural, changes of the P-cluster suggest a role for this cluster in coupling, electron transfer and proton transfer in nitrogenase.
About this StructureAbout this Structure
2MIN is a Protein complex structure of sequences from Azotobacter vinelandii with CA, HCA, CLF and CFM as ligands. This structure superseeds the now removed PDB entry 1MIN. Active as Nitrogenase, with EC number 1.18.6.1 Full crystallographic information is available from OCA.
ReferenceReference
Redox-dependent structural changes in the nitrogenase P-cluster., Peters JW, Stowell MH, Soltis SM, Finnegan MG, Johnson MK, Rees DC, Biochemistry. 1997 Feb 11;36(6):1181-7. PMID:9063865
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