Ferredoxin: Difference between revisions
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[[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. | [[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=''> | |||
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.]] | |||
Two forms of D14C [3Fe-4S] ''Pyrococcus furiosus'' ferredoxin are obtained when purified at pH 8.0: a monomer and a dimer connected by an intermolecular disulfide bond (see static image at the left). When purified at pH 5.8, only the monomer is obtained. The [3Fe-4S] form diffracted to 2.8 Å resolution and showed only the <scene name='Journal:JBIC:10/Cv1/13'>monomeric form, which resembles molecule A of D14C [4Fe-4S] Pyrococcus furiosus ferredoxin</scene>. Crystal packing in <scene name='Journal:JBIC:10/Cv2/7'>D14C [3Fe-4S] ferredoxin is as extended beta-sheet dimers of adjacent molecules</scene> (shown in <font color='red'><b>red</b></font> and <font color='orange'><b>orange</b></font>), which is the same as <scene name='Journal:JBIC:10/Cv2/9'>WT [3Fe-4S] P. furiosus ferredoxin</scene> ([[1sj1]], shown in <font color='blue'><b>blue</b></font> and <font color='cyan'><b>cyan</b></font>) even though the space groups are different (see also corresponding side views for <scene name='Journal:JBIC:10/Cv2/8'>D14C [3Fe-4S]</scene>) and <scene name='Journal:JBIC:10/Cv2/10'>WT [3Fe-4S]</scene>).<ref>DOI 10.1007/s00775-011-0778-7</ref> | |||
</StructureSection> | |||
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[[1b9r]] – TER – Pseudomonas - NMR <br /> | [[1b9r]] – TER – Pseudomonas - NMR <br /> | ||
==Reference== | |||
<references/> | |||
[[Category:Topic Page]] | [[Category:Topic Page]] | ||
[[Category:Iron]] | [[Category:Iron]] | ||
