Unambiguous Assignment of Reduction Potentials in Diheme Cytochromes

Area of Science:

• Biophysical Chemistry
• Computational Biology
• Protein Science

Background:

• Cytochrome c proteins are crucial for electron transfer.
• Diheme cytochrome c (DHC) presents complex redox behavior.
• Experimental determination of reduction potentials (E ⁰ ) is vital but challenging for multicenter proteins.

Purpose of the Study:

• To assign experimentally determined reduction potentials to specific heme groups in DHC.
• To validate the perturbed matrix method for analyzing multicenter redox proteins.

Main Methods:

• Utilized perturbed matrix method calculations.
• Applied the method to a diheme cytochrome c protein model.
• Compared calculated reduction potentials with existing experimental data.

Main Results:

• Achieved very good agreement between calculated and experimental reduction potentials.
• Successfully assigned specific E ⁰ values to individual heme groups within DHC.
• Demonstrated the predictive capability of the computational approach.

Conclusions:

• The perturbed matrix method is a reliable tool for predicting redox thermodynamic properties of multicenter redox proteins.
• This method can be used independently or in conjunction with experimental techniques.
• Provides a detailed understanding of electron transfer processes in complex biological systems.