Long-range electron-electron interaction and charge transfer in protein complexes: a numerical approach.

Area of Science:

• Biochemistry
• Computational Biology
• Physical Chemistry

Background:

• Electron transfer is crucial in biological processes.
• Accurately modeling large protein complexes is computationally challenging.

Purpose of the Study:

• To develop a computational strategy for the energy landscape of electron transfer in large biochemical systems.
• To apply this strategy to the nitrite reductase hexameric protein complex (NrfH2A4) from Desulfovibrio vulgaris.

Main Methods:

• Numerical solution of the Poisson-Boltzmann equation for small complexes.
• A verified pair approximation for larger systems.
• Analysis of effective Coulomb interactions and their dependence on intersite distance.

Main Results:

• The pair approximation effectively models electron transfer energy landscapes in large systems.
• Effective Coulomb interactions can reach 200 meV and depend non-trivially on distance.
• Strong Coulomb interactions significantly impact protein complex charging thermodynamics and kinetics.

Conclusions:

• The proposed strategy provides a robust method for studying electron transfer in complex biological molecules.
• Understanding Coulomb interactions is key to predicting protein complex function.
• The influence of biomembrane embedding on electron transfer was also considered.