Fundamentals of Electron Transfer in Proteins

摘要: An outline of the Marcus–Levich–Dogonadze theory charge transfer reactions in polar media is given with an emphasis on physical sense its concepts rather than mathematical details. The reorganization energy has been considered as well dependence activation this parameter and reaction energy. quantum—mechanical treatment pre-exponential factor described, regularities non-adiabatic adiabatic electron are qualitatively explained. Regarding intraprotein transfer, electrostatic interaction a moving surroundings, primarily protein water, major determining thermodynamics kinetics involved. A specific feature structure presence high concentration strongly groups, mainly peptide groups. Tight packing these dipoles inside certain structures substantially restricts their ability to change orientation external electric field. This two consequences: (i) low static dielectric permittivity (i.e., constant) proteins (ii) substantial permanent field pre-existent before charging active site, e.g., redox center. Therefore, internal environment can be defined pre-organized highly-polar, low-dielectric medium. These features important for acceleration reactions. semi-continuum electrostatics approach, viz. description set point atomic charges continuum presented. specificity quantitative calculations framework approach all parameters considered. It shown that pre-existing should calculated employing protein’s optical permittivity, while response one use quantity (in both cases, constant water). does not depend energies by microscopic simulations (including quantum—chemical data) reasonable agreement each other experiment. mechanism long-range discussed.