1C6S

THE SOLUTION STRUCTURE OF CYTOCHROME C6 FROM THE THERMOPHILIC CYANOBACTERIUM SYNECHOCOCCUS ELONGATUS, NMR, 20 STRUCTURES

Summary for 1C6S

• Entry DOI: 10.2210/pdb1c6s/pdb
• Descriptor: CYTOCHROME C6, HEME C (2 entities in total)
• Functional Keywords: cytochrome c6, electron transport, photosynthesis, synechococcus elongatus
• Biological source: Synechococcus elongatus
• Cellular location: Cellular thylakoid lumen (Potential): P0A3Y0
• Total number of polymer chains: 1
• Total formula weight: 9805.87

Authors

Roesch, P.,Beissinger, M.,Sticht, H.,Sutter, M.,Ejchart, A.,Haehnel, W. (deposition date: 1997-03-31, release date: 1998-04-08, Last modification date: 2024-10-16)

Primary citation

Beissinger, M.,Sticht, H.,Sutter, M.,Ejchart, A.,Haehnel, W.,Rosch, P.
Solution structure of cytochrome c6 from the thermophilic cyanobacterium Synechococcus elongatus.
EMBO J., 17:27-36, 1998

PubMed Abstract: Cytochrome c6 is a small, soluble electron carrier between the two membrane-bound complexes cytochrome b6f and photosystem I (PSI) in oxygenic photosynthesis. We determined the solution structure of cytochrome c6 from the thermophilic cyanobacterium Synechococcus elongatus by NMR spectroscopy and molecular dynamics calculations based on 1586 interresidual distance and 28 dihedral angle restraints. The overall fold exhibits four alpha-helices and a small antiparallel beta-sheet in the vicinity of Met58, one of the axial heme ligands. The flat hydrophobic area in this cytochrome c6 is conserved in other c6 cytochromes and even in plastocyanin of higher plants. This docking region includes the site of electron transfer to PSI and possibly to the cytochrome b6f complex. The binding of cytochrome c6 to PSI in green algae involves interaction of a negative patch with a positive domain of PSI. This positive domain has not been inserted at the evolutionary level of cyanobacteria, but the negatively charged surface region is already present in S. elongatus cytochrome c6 and may thus have been optimized during evolution to improve the interaction with the positively charged cytochrome f. As the structure of PSI is known in S.elongatus, the reported cytochrome c6 structure can provide a basis for mutagenesis studies to delineate the mechanism of electron transfer between both.

PubMed: 9427738
DOI: 10.1093/emboj/17.1.27

Experimental method

SOLUTION NMR