1GKS

ECTOTHIORHODOSPIRA HALOPHILA CYTOCHROME C551 (REDUCED), NMR, 37 STRUCTURES

Summary for 1GKS

• Entry DOI: 10.2210/pdb1gks/pdb
• Descriptor: CYTOCHROME C551, PROTOPORPHYRIN IX CONTAINING FE (2 entities in total)
• Functional Keywords: bacterial cytochrome c, halophilic purple phototrophic bacterium, electron transport
• Biological source: Halorhodospira halophila
• Total number of polymer chains: 1
• Total formula weight: 8881.51

Authors

Bersch, B.,Blackledge, M.J.,Meyer, T.E.,Marion, D. (deposition date: 1996-07-16, release date: 1997-01-27, Last modification date: 2024-10-30)

Primary citation

Bersch, B.,Blackledge, M.J.,Meyer, T.E.,Marion, D.
Ectothiorhodospira halophila ferrocytochrome c551: solution structure and comparison with bacterial cytochromes c.
J.Mol.Biol., 264:567-584, 1996

PubMed Abstract: 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.

PubMed: 8969306
DOI: 10.1006/jmbi.1996.0662

Experimental method

SOLUTION NMR