1rwj
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c7-type three-heme cytochrome domain
OverviewOverview
The structure of a novel c(7)-type cytochrome domain that has two, bishistidine coordinated hemes and one heme with histidine, methionine, coordination (where the sixth ligand is a methionine residue) was, determined at 1.7 A resolution. This domain is a representative of domains, that form three polymers encoded by the Geobacter sulfurreducens genome., Two of these polymers consist of four and one protein of nine c(7)-type, domains with a total of 12 and 27 hemes, respectively. Four individual, domains (termed A, B, C, and D) from one such multiheme cytochrome c, (ORF03300) were cloned and expressed in Escherichia coli. The domain C, produced diffraction quality crystals from 2.4 M sodium malonate (pH 7)., The structure was solved by MAD method and refined to an R-factor of 19.5%, and R-free of 21.8%. Unlike the two c(7) molecules with known structures, one from G. sulfurreducens (PpcA) and one from Desulfuromonas acetoxidans, where all three hemes are bishistidine coordinated, this domain contains a, heme which is coordinated by a methionine and a histidine residue. As a, result, the corresponding heme could have a higher potential than the, other two hemes. The apparent midpoint reduction potential, E(app), of, domain C is -105 mV, 50 mV higher than that of PpcA.
About this StructureAbout this Structure
1RWJ is a Single protein structure of sequence from Geobacter sulfurreducens with HEM as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structure of a novel c7-type three-heme cytochrome domain from a multidomain cytochrome c polymer., Pokkuluri PR, Londer YY, Duke NE, Erickson J, Pessanha M, Salgueiro CA, Schiffer M, Protein Sci. 2004 Jun;13(6):1684-92. Epub 2004 May 7. PMID:15133162
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