2MIN

NITROGENASE MOFE PROTEIN FROM AZOTOBACTER VINELANDII, OXIDIZED STATE

Replaces:  1MIN

Summary for 2MIN

• Entry DOI: 10.2210/pdb2min/pdb
• Descriptor: NITROGENASE MOLYBDENUM IRON PROTEIN, 3-HYDROXY-3-CARBOXY-ADIPIC ACID, FE(8)-S(7) CLUSTER, ... (7 entities in total)
• Functional Keywords: nitrogen fixation, nitrogen metabolism, oxidoreductase, molybdoenzymes, biological nitrogen fixation
• Biological source: Azotobacter vinelandii; More
• Total number of polymer chains: 4
• Total formula weight: 232658.83

Authors

Peters, J.W.,Stowell, M.H.B.,Soltis, S.M.,Day, M.W.,Kim, J.,Rees, D.C. (deposition date: 1996-12-20, release date: 1997-04-01, Last modification date: 2024-02-21)

Primary citation

Peters, J.W.,Stowell, M.H.,Soltis, S.M.,Finnegan, M.G.,Johnson, M.K.,Rees, D.C.
Redox-dependent structural changes in the nitrogenase P-cluster.
Biochemistry, 36:1181-1187, 1997

PubMed Abstract: 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.

PubMed: 9063865
DOI: 10.1021/bi9626665

Experimental method

X-RAY DIFFRACTION (2.03 Å)