We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Transient binding of plastocyanin to its physiological redox partners modifies the copper site geometry
- Authors
Díaz-Moreno, Irene; Díaz-Quintana, Antonio; Díaz-Moreno, Sofía; Subías, Gloria; De la Rosa, Miguel A.
- Abstract
Abstract: The transient complexes of plastocyanin with cytochrome f and photosystem I are herein used as excellent model systems to investigate how the metal sites adapt to the changes in the protein matrix in transient complexes that are involved in redox reactions. Thus, both complexes from the cyanobacterium Nostoc sp. PCC 7119 (former Anabaena sp. PCC 7119) have been analysed by X-ray absorption spectroscopy. Our data are consistent with a significant distortion of the trigonal pyramidal geometry of the Cu coordination sphere when plastocyanin binds to cytochrome f, no matter their redox states are. The resulting tetrahedral geometry shows a shortening of the distance between Cu and the Sδ atom of its ligand Met-97, with respect to the crystallographic structure of free plastocyanin. On the other hand, when plastocyanin binds to photosystem I instead of cytochrome f, the geometric changes are not significant but a displacement in charge distribution around the metal centre can be observed. Noteworthy, the electronic density around the Cu atom increases or decreases when oxidised plastocyanin binds to cytochrome f or photosystem I, respectively, thus indicating that the protein matrix affects the electron transfer between the two partners during their transient interaction.
- Subjects
EXTENDED X-ray absorption fine structure; ABSORPTION; METALLOPROTEINS; OXIDATION-reduction reaction
- Publication
FEBS Letters, 2006, Vol 580, Issue 26, p6187
- ISSN
0014-5793
- Publication type
Article
- DOI
10.1016/j.febslet.2006.10.020