Electron transfers in proteins: investigations with a modified through-bond coupling model

Area of Science:

• * Biophysical Chemistry
• * Computational Biology
• * Molecular Biophysics

Background:

• * Existing models for electron coupling in biological systems have limitations.
• * Understanding electron transfer pathways is vital for deciphering biological processes.

Purpose of the Study:

• * To develop an improved model for calculating through-bond electronic coupling.
• * To identify dominant electron coupling pathways in polypeptide chains.
• * To characterize the influence of local protein structure on electron transfer.

Main Methods:

• * Development and application of a modified through-bond coupling (MTBC) model.
• * Analysis of electron coupling pathways in polypeptide chains.
• * Correlation of structural features (e.g., N-H bonds, carbonyl distances, trans-configurations) with coupling strength and decay factors.

Main Results:

• * The MTBC model demonstrates significant improvement over previous models.
• * N-H bonds were identified as essential for electron coupling in polypeptides.
• * Local peptide and protein structures, including carbonyl O-O distances and deviations from trans-configurations, finely characterize electron couplings.
• * Hydrogen bonds serve as a primary pathway for electron transfer between non-sequential amino acids.

Conclusions:

• * The MTBC model provides a more accurate description of electron coupling.
• * The findings highlight the critical role of specific bonds and structural motifs in mediating electron transfer.
• * The MTBC model, combined with the fragment approach, is effective for studying electron transfer in complex biological systems.