1ctj

<table><tr><td colspan='2'>[[1ctj]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Monoraphidium_braunii Monoraphidium braunii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CTJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CTJ FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene></td></tr>

[[https://www.uniprot.org/uniprot/CYC6_CHLBR CYC6_CHLBR]] Functions as an electron carrier between membrane-bound cytochrome b6-f and photosystem I in oxygenic photosynthesis.

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== Publication Abstract from PubMed ==

BACKGROUND: Electron transfer between cytochrome f and photosystem I (PSI) can be accomplished by the heme-containing protein cytochrome c6 or by the copper-containing protein plastocyanin. Higher plants use plastocyanin as the only electron donor to PSI, whereas most green algae and cyanobacteria can use either, with similar kinetics, depending on the copper concentration in the culture medium. RESULTS: We report here the determination of the structure of cytochrome c6 from the green alga Monoraphidium braunii. Synchrotron X-ray data with an effective resolution of 1.2 A and the presence of one iron and three sulfur atoms enabled, possibly for the first time, the determination of an unknown protein structure by ab initio methods. Anisotropic refinement was accompanied by a decrease in the 'free' R value of over 7% the anisotropic motion is concentrated at the termini and between residues 38 and 53. The heme geometry is in very good agreement with a new set of heme distances derived from the structures of small molecules. This is probably the most precise structure of a heme protein to date. CONCLUSIONS: On the basis of this cytochrome c6 structure, we have calculated potential electron transfer pathways and made comparisons with similar analyses for plastocyanin. Electron transfer between the copper redox center of plastocyanin to PSI and from cytochrome f is believed to involve two sites on the protein. In contrast, cytochrome c6 may well use just one electron transfer site, close to the heme unit, in its corresponding reactions with the same two redox partners.

Ab initio determination of the crystal structure of cytochrome c6 and comparison with plastocyanin.,Frazao C, Soares CM, Carrondo MA, Pohl E, Dauter Z, Wilson KS, Hervas M, Navarro JA, De la Rosa MA, Sheldrick GM Structure. 1995 Nov 15;3(11):1159-69. PMID:8591027<ref>PMID:8591027</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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==See Also==

*[[Cytochrome C 3D structures|Cytochrome C 3D structures]]

== References ==

<references/>

[[Category: Sheldrick, G M]]

[[Category: Heme]]