A further investigation of the cytochrome b5–cytochrome c complex

• Autor(es): Banci, Lucia ; Bertini, Ivano ; Moura, José J. G. ; Felli, Isabella C. ; Krippahl, Ludwig ; Kubicek, Karel
• Data: 2003
• Identificador Persistente: http://hdl.handle.net/10362/8719
• Origem: Repositório Institucional da UNL
• Tipo de Documento: Artigo
• Idioma: Inglês

Descrição

J Biol Inorg Chem (2003) 8: 777–786 DOI 10.1007/s00775-003-0479-y The interaction of reduced rabbit cytochrome b(5) with reduced yeast iso-1 cytochrome c has been studied through the analysis of (1)H-(15)N HSQC spectra, of (15)N longitudinal ( R(1)) and transverse ( R(2)) relaxation rates, and of the solvent exchange rates of protein backbone amides. For the first time, the adduct has been investigated also from the cytochrome c side. The analysis of the NMR data was integrated with docking calculations. The result is that cytochrome b(5) has two negative patches capable of interacting with a single positive surface area of cytochrome c. At low protein concentrations and in equimolar mixture, two different 1:1 adducts are formed. At high concentration and/or with excess cytochrome c, a 2:1 adduct is formed. All the species are in fast exchange on the scale of differences in chemical shift. By comparison with literature data, it appears that the structure of one 1:1 adduct changes with the origin or primary sequence of cytochrome b(5).