1gks
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ECTOTHIORHODOSPIRA HALOPHILA CYTOCHROME C551 (REDUCED), NMR, 37 STRUCTURES
OverviewOverview
The solution structure of the Ectothiorhodospira halophila ferrocytochrome, c551 has been determined. This molecule belongs to a separate class of, small bacterial cytochromes c for which no 3D structure has been reported, so far. It is characterized by a very low redox potential (58 mV) and is, isolated from the periplasm of halophilic purple phototrophic bacteria., For the 78 residue protein, 1445 NOE derived distance constraints were, used in a combined simulated annealing/restrained molecular dynamics, calculation. The final ensemble of 37 structures presents a backbone, r.m.s.d. of less than 0.5 A compared to the mean structure. The physical, viability of these structures was investigated by subjecting eight of them, to a constraint free molecular dynamics simulation. No systematic, conformational change was observed and the average backbone r.m.s.d., compared to the initial structures was less than 1.5 A. The structure of, the E. halophila cytochrome c551 shows a striking resemblance to, Azotobacter vinelandii cytochrome c5. Significant differences in backbone, conformations occur in three small regions which are implicated in solvent, protection of the heme propionates and thiomethyl-8(1). Comparison with, Pseudomonas aeruginosa cytochrome c551 reveals that only the common, cytochrome c core, i.e. three helices, is conserved. The folding of the, protein chain around the heme propionates is very different and results in, more efficient solvent protection in Ps. aeruginosa. The electrostatic, surface of E. halophila cytochrome c551 was found to be significantly, different from mitochondrial cytochromes c and bacterial cytochromes c2, but similar to that of Ps. aeruginosa cytochrome c551.
About this StructureAbout this Structure
1GKS is a Single protein structure of sequence from Halorhodospira halophila with HEM as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Ectothiorhodospira halophila ferrocytochrome c551: solution structure and comparison with bacterial cytochromes c., Bersch B, Blackledge MJ, Meyer TE, Marion D, J Mol Biol. 1996 Dec 6;264(3):567-84. PMID:8969306
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