The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS.
The transient complex between cytochrome f and plastocyanin from the cyanobacterium Nostoc sp. PCC 7119 has been analysed by X-ray Absorption Spectroscopy in solution, using both proteins in their oxidized and reduced states. Fe K-edge data mainly shows that the atypical metal coordination geometry of cytochrome f, in which the N-terminal amino acid acts as an axial ligand of the heme group, remains unaltered upon binding to its redox partner, plastocyanin. This fact suggests that cytochrome f provides a stable binding site for plastocyanin and minimizes the reorganization energy required in the transient complex formation, which could facilitate the electron transfer between the two redox partners.
Díaz-Moreno
Irene
I
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y Consejo Superior de Investigaciones Científicas, Américo Vespucio 49, 41092, Sevilla, Spain. irene.diazmoreno@nimr.mrc.ac.uk
Díaz-Moreno
Sofía
S
Subías
Gloria
G
De la Rosa
Miguel A
MA
Díaz-Quintana
Antonio
A
D015502:Absorptiometry, Photon; D045348:Cytochromes f / Q000737:chemistry* / Q000378:metabolism*; D008024:Ligands; D046937:Nostoc / Q000378:metabolism*; D010970:Plastocyanin / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics
D008024:Ligands; D010970:Plastocyanin; D045348:Cytochromes f