Ferredoxin: Difference between revisions

[[Image:1vjw.png|left|150px]]<br />

{{STRUCTURE_1vjw|  PDB=1vjw  |  SCENE=Ferredoxin/Cv/1  }}  

[[Ferredoxin]] (Fd) is found in chloroplasts which mediates electron transfer and contains an iron-sulfur cluster.  It is involved in the photosynthesis process where its iron atoms accept or discharge electrons when they are being oxidized or reduced.  The iron-sulfur cluster can contain 2Fe-2S and is termed plant-like or 3Fe-4S or 4Fe-4S clusters (''e.g.'' 4Fe-4S ''Thermotoga maritima'' [[1vjw]] to the right).  '''Adrenodoxin''' (ADR) is a ferredoxin containing a 2Fe-2S group involved in electron transfer from NADPH+ to a cytochrome P-450 in the adrenal gland.  '''Putidaredoxin''' (PUT) and '''terpredoxin''' (TER) are involved in the same reaction in bacteria and contain a 2Fe-2S group.

<StructureSection load='2Z8Qa.pdb' size='500' side='right' scene='Journal:JBIC:10/Cv1/2' caption='4Fe-4S ferredoxin complex with Co (III) hexamine [[2z8q]]'>

Structures of the all cysteinyl coordinated D14C variant of ferredoxin from the hyperthermophilic archaeon ''Pyrococcus furiosus'' have been determined for the <scene name='Journal:JBIC:10/Cv1/5'>[4Fe-4S]</scene> <-> and <scene name='Journal:JBIC:10/Cv1/6'>[3Fe-4S]</scene> forms (<scene name='Journal:JBIC:10/Cv1/8'>click to enlarge</scene>). The [4Fe-4S] form diffracted to 1.7 Å and two different types of molecules were found in the crystal ([[2z8q]]). They have different crystal packing and intramolecular disulfide bond conformation. The crystal packing reveals a <scene name='Journal:JBIC:10/Cv/5'>beta-sheet interaction between A molecules</scene> (shown in <font color='blue'><b>blue</b></font> and <span style="color:green;background-color:black;font-weight:bold;">green</span>) in adjacent asymmetric units, while <scene name='Journal:JBIC:10/Cv/6'>B molecules are packed as monomers in a less rigid position next to the A-A extended beta-sheet dimers</scene> (shown in <font color='red'><b>red</b></font> and <span style="color:yellow;background-color:black;font-weight:bold;">yellow</span>). The <scene name='Journal:JBIC:10/Cv1/9'>intramolecular disulfide bond in the A molecules is in a double conformation</scene> while the intramolecular disulfide bond in the <scene name='Journal:JBIC:10/Cv1/10'>B molecules is in a single conformation</scene> (<scene name='Journal:JBIC:10/Cv1/11'>click to see morph</scene>, molecule A is shown in <font color='blue'><b>blue</b></font> and molecule B in <span style="color:green;background-color:black;font-weight:bold;">green</span>).

[[Image:Schem1.png|left|300px|thumb|pH dependent equilibrium of D14C [3Fe-4S] ''P. furiosus'' ferredoxin between protonated and deprotonated monomers and formation of a disulfide bonded dimer from deprotonated monomers. Fd is short for ferredoxin.]]

</StructureSection>

<StructureSection load='1stp' size='500' side='right' scene='Journal:JBIC:12/Cv/2' caption=''>

Biological iron-sulfur (Fe-S) clusters are functionally versatile, modular prosthetic groups. The electronic structure and the site of iron reduction of these protein-bound cofactors account for the electron transfer function and mechanism. In the present work we have solved the structure of the ISC-like [2Fe-2S] ferredoxin called FdxB from the non-pathogenic gammaproteobacterium ''Pseudomonas putida'' JCM 20004 (formerly ''Pseudomonas ovalis'' IAM 1002). This FdxB protein contains an adrenodoxin (Adx) like, redox-active [2Fe-2S] cluster, which plays an essential role in the de novo iron-sulfur cluster assembly (ISC) system. It is encoded by the fdxB gene as a constituent of the cognate iscR-iscS1-iscU-iscA-hscB-hscA-fdxB gene cluster for the ISC system (DDBJ-EMBL-GenBank code AB109467). In ''P. putida'' the ISC pathway is apparently the sole system for ''in vivo'' Fe-S cluster assembly whereas the SUF pathway is missing in the bacterial genome (unlike in ''Escherichia coli'').

[[1b9r]] – TER – ''Pseudomonas'' - NMR <br />

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[[Category:Topic Page]]

[[Category:Iron]]