1c6s
From Proteopedia
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THE SOLUTION STRUCTURE OF CYTOCHROME C6 FROM THE THERMOPHILIC CYANOBACTERIUM SYNECHOCOCCUS ELONGATUS, NMR, 20 STRUCTURES
Overview
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.
About this Structure
1C6S is a Single protein structure of sequence from Synechococcus elongatus with HEC as ligand. Full crystallographic information is available from OCA.
Reference
Solution structure of cytochrome c6 from the thermophilic cyanobacterium Synechococcus elongatus., Beissinger M, Sticht H, Sutter M, Ejchart A, Haehnel W, Rosch P, EMBO J. 1998 Jan 2;17(1):27-36. PMID:9427738
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