View source for 2min

[[Image:2min.gif|left|200px]]<br /><applet load="2min" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="2min, resolution 2.03&Aring;" />
'''NITROGENASE MOFE PROTEIN FROM AZOTOBACTER VINELANDII, OXIDIZED STATE'''<br />

==Overview==
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 Structure==
2MIN is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=HCA:'>HCA</scene>, <scene name='pdbligand=CLF:'>CLF</scene> and <scene name='pdbligand=CFM:'>CFM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1MIN. Active as [http://en.wikipedia.org/wiki/Nitrogenase Nitrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.18.6.1 1.18.6.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2MIN OCA]. 

==Reference==
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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9063865 9063865]
[[Category: Azotobacter vinelandii]]
[[Category: Nitrogenase]]
[[Category: Protein complex]]
[[Category: Day, M W.]]
[[Category: Kim, J.]]
[[Category: Peters, J W.]]
[[Category: Rees, D C.]]
[[Category: Soltis, S M.]]
[[Category: Stowell, M H.B.]]
[[Category: CA]]
[[Category: CFM]]
[[Category: CLF]]
[[Category: HCA]]
[[Category: biological nitrogen fixation]]
[[Category: molybdoenzymes]]
[[Category: nitrogen fixation]]
[[Category: nitrogen metabolism]]
[[Category: oxidoreductase]]

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