2pcf
From Proteopedia
THE COMPLEX OF CYTOCHROME F AND PLASTOCYANIN DETERMINED WITH PARAMAGNETIC NMR. BASED ON THE STRUCTURES OF CYTOCHROME F AND PLASTOCYANIN, 10 STRUCTURES
Structural highlights
FunctionCYF_BRARR Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBACKGROUND: The reduction of plastocyanin by cytochrome f is part of the chain of photosynthetic electron transfer reactions that links photosystems II and I. The reaction is rapid and is influenced by charged residues on both proteins. Previously determined structures show that the plastocyanin copper and cytochrome f haem redox centres are some distance apart from the relevant charged sidechains, and until now it was unclear how a transient electrostatic complex can be formed that brings the redox centres sufficiently close for a rapid reaction. RESULTS: A new approach was used to determine the structure of the transient complex between cytochrome f and plastocyanin. Diamagnetic chemical shift changes and intermolecular pseudocontact shifts in the NMR spectrum of plastocyanin were used as input in restrained rigid-body molecular dynamics calculations. An ensemble of ten structures was obtained, in which the root mean square deviation of the plastocyanin position relative to cytochrome f is 1.0 A. Electrostatic interaction is maintained at the same time as the hydrophobic side of plastocyanin makes close contact with the haem area, thus providing a short electron transfer pathway (Fe-Cu distance 10.9 A) via residues Tyr1 or Phe4 (cytochrome f) and the copper ligand His87 (plastocyanin). CONCLUSIONS: The combined use of diamagnetic and paramagnetic chemical shift changes makes it possible to obtain detailed information about the structure of a transient complex of redox proteins. The structure suggests that the electrostatic interactions 'guide' the partners into a position that is optimal for electron transfer, and which may be stabilised by short-range interactions. The structure of the complex of plastocyanin and cytochrome f, determined by paramagnetic NMR and restrained rigid-body molecular dynamics.,Ubbink M, Ejdeback M, Karlsson BG, Bendall DS Structure. 1998 Mar 15;6(3):323-35. PMID:9551554[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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