View source for 2v08


==Structure of wild-type Phormidium laminosum cytochrome c6==
<StructureSection load='2v08' size='340' side='right' caption='[[2v08]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2v08]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Phola Phola]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2V08 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2V08 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=IMD:IMIDAZOLE'>IMD</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2v08 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2v08 OCA], [http://pdbe.org/2v08 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2v08 RCSB], [http://www.ebi.ac.uk/pdbsum/2v08 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2v08 ProSAT]</span></td></tr>
</table>
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/v0/2v08_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2v08 ConSurf].
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== Publication Abstract from PubMed ==
Cytochrome c6A is a unique dithio-cytochrome of green algae and plants. It has a very similar core structure to that of bacterial and algal cytochromes c6 but is unable to fulfill the same function of transferring electrons from cytochrome f to photosystem I. A key feature is that its heme midpoint potential is more than 200 mV below that of cytochrome c6 despite having His and Met as axial heme-iron ligands. To identify the molecular origins of the difference in potential, the structure of cytochrome c6 from the cyanobacterium Phormidium laminosum has been determined by X-ray crystallography and compared with the known structure of cytochrome c6A. One salient difference of the heme pockets is that a highly conserved Gln (Q51) in cytochrome c6 is replaced by Val (V52) in c6A. Using protein film voltammetry, we found that swapping these residues raised the c6A potential by +109 mV and decreased that of c6 by almost the same extent, -100 mV. X-ray crystallography of the V52Q protein showed that the Gln residue adopts the same configuration relative to the heme as in cytochrome c6 and we propose that this stereochemistry destabilizes the oxidized form of the heme. Consequently, replacement of Gln by Val was probably a key step in the evolution of cytochrome c6A from cytochrome c6, inhibiting reduction by the cytochrome b6f complex and facilitating establishment of a new function.

Modulation of heme redox potential in the cytochrome c6 family.,Worrall JA, Schlarb-Ridley BG, Reda T, Marcaida MJ, Moorlen RJ, Wastl J, Hirst J, Bendall DS, Luisi BF, Howe CJ J Am Chem Soc. 2007 Aug 1;129(30):9468-75. Epub 2007 Jul 11. PMID:17625855<ref>PMID:17625855</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2v08" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome c|Cytochrome c]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Phola]]
[[Category: Bendall, D S]]
[[Category: Hirst, J]]
[[Category: Howe, C J]]
[[Category: Luisi, B F]]
[[Category: Marcaida, M J]]
[[Category: Moorlen, R J]]
[[Category: Reda, T]]
[[Category: Schlarb-Ridley, B G]]
[[Category: Wastl, J]]
[[Category: Worrall, J A.R]]
[[Category: Cyano-bacteria]]
[[Category: Cytochrome]]
[[Category: Electron-transfer]]
[[Category: Photosynthesis]]