Please use this identifier to cite or link to this item:
logo share SHARE logo core CORE BASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE

The transient complex of poplar plastocyanin with cytochrome f: effects of ionic strength and pH

AuthorsLange, Christian; Cornvik, Tobias; Díaz-Moreno, Irene CSIC ORCID; Ubbink, Marcellus
KeywordsElectron transfer
Protein complex
NMR spectroscopy
Transient complex
Issue DateApr-2005
CitationBiochimica et Biophysica Acta - Bioenergetics 1707(2-3): 179-188 (2005)
AbstractThe orientation of poplar plastocyanin in the complex with turnip cytochrome f has been determined by rigid-body calculations using restraints from paramagnetic NMR measurements. The results show that poplar plastocyanin interacts with cytochrome f with the hydrophobic patch of plastocyanin close to the heme region on cytochrome f and via electrostatic interactions between the charged patches on both proteins. Plastocyanin is tilted relative to the orientation reported for spinach plastocyanin, resulting in a longer distance between iron and copper (13.9 A). With increasing ionic strength, from 0.01 to 0.11 M, all observed chemical-shift changes decrease uniformly, supporting the idea that electrostatic forces contribute to complex formation. There is no indication for a rearrangement of the transient complex in this ionic strength range, contrary to what had been proposed earlier on the basis of kinetic data. By decreasing the pH from pH 7.7 to pH 5.5, the complex is destabilized. This may be attributed to the protonation of the conserved acidic patches or the copper ligand His87 in poplar plastocyanin, which are shown to have similar pK(a) values. The results are interpreted in a two-step model for complex formation.
Description10 páginas, 7 figuras
Publisher version (URL)
Appears in Collections:(IBVF) Artículos

Show full item record
Review this work

Page view(s)

checked on May 21, 2022

Google ScholarTM




WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.