2a3m
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Structure of Desulfovibrio desulfuricans G20 tetraheme cytochrome (oxidized form)
OverviewOverview
The structure of the type I tetraheme cytochrome c(3) from Desulfovibrio desulfuricans G20 was determined to 1.5 Angstrom by X-ray crystallography. In addition to the oxidized form, the structure of the molybdate-bound form of the protein was determined from oxidized crystals soaked in sodium molybdate. Only small structural shifts were obtained with metal binding, consistent with the remarkable structural stability of this protein. In vitro experiments with pure cytochrome showed that molybdate could oxidize the reduced cytochrome, although not as rapidly as U(VI) present as uranyl acetate. Alterations in the overall conformation and thermostability of the metal-oxidized protein were investigated by circular dichroism studies. Again, only small changes in protein structure were documented. The location of the molybdate ion near heme IV in the crystal structure suggested heme IV as the site of electron exit from the reduced cytochrome and implicated Lys14 and Lys56 in binding. Analysis of structurally conserved water molecules in type I cytochrome c(3) crystal structures identified interactions predicted to be important for protein stability and possibly for intramolecular electron transfer among heme molecules.
About this StructureAbout this Structure
2A3M is a Single protein structure of sequence from Desulfovibrio desulfuricans with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Desulfovibrio desulfuricans G20 tetraheme cytochrome structure at 1.5 Angstrom and cytochrome interaction with metal complexes., Pattarkine MV, Tanner JJ, Bottoms CA, Lee YH, Wall JD, J Mol Biol. 2006 May 19;358(5):1314-27. Epub 2006 Mar 23. PMID:16580681
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