Responsable: José María Ortega Rodríguez
Tipo de Proyecto/Ayuda: Proyecto Internacional (EU)
Referencia: INTAS99-00281
Web: http://cordis.europa.eu/projects/rcn/65964_en.html
Fecha de Inicio: 01-05-2000
Fecha de Finalización: 30-04-2003

Empresa/Organismo financiador/es:

• INTAS (International Association for the promotion of co-operation with scientists)

Socios:

• Leiden University (Gerard Canters)
• Direction des Sciences du Vivant (Paul Mathis)
• Institute of Problems of Chemical Physics of the Russian Academy of Sciences (Alexander Kotelnikov)
• Moscow State University (Andrei Rubin)
• Institute of Mathematical Problems of Biology (Nikolai Balabaev)

Resumen del proyecto:

The long-range electron transfer (LRET) is the key step of functioning of bacterial reaction centres (RC), cytochrome oxidase and nitrogenase. Many LRET reactions in proteins on a time scale of 10-9-10-3s are studied. Recently all LRET reactions in proteins have been described by the nonadiabatic limit of Marcus theory, where Ket~Vab2 and does not depend on n, if Vab2<
This project is the development of a new mixed adiabatic/nonadiabatic model of LRET, combined with the Rips-Jortner and Sumi-Marcus approaches. Two reaction coordinates - fast (vibrational, temperature independent) and slow (diffusive, temperature dependent) with different contributions lv and ld to the reorganization energy along these coordinates will be considered. The broad distribution of relaxation times along the diffusive coordinate will be described in accordance with Davidson-Cole theory by parameters n and b. The aim of the project is the experimental investigation of the real mechanism of LRET in RC and in metal containing proteins within the mixed adiabatic/nonadiabatic model taking into consideration the correlation between the kinetics of LRET and the dynamics of protein reorganization.

The photostimulated LRET between donor and acceptor centres in RC, chemically or mutatant modified Mb, Hb, Cyt c, Cyt-c550 and azurin will be studied as a function of the protein and solvent dynamics at different temperatures, pH and solvent viscosities. The parameters n and b will be extracted from measurements of the time resolved band shifts in the phosphorescence spectra of the chromophores used. The equilibrium dynamics will be estimated by multi-dimensional homo- and hetero-nuclear hf NMR. Computer molecular dynamics simulation and electrostatic calculations will be performed for comparison with experimental investigations. The results obtained will allow for comparison and an explanation of the experimental data on the kinetics of LRET in various proteins at room temperature and lower. It will be demonstrated, that the dynamical organisation of protein macromolecules may be specific for different proteins, can alter the functional properties of proteins by some orders of magnitude and may be as important as the chemical structure of active centres. It will be a significant contribution in solving a fundamental problem of modern molecular biology, which deals with the relation between structural and dynamical properties of proteins and their functions.