Photoinduced hole hopping through tryptophans in proteins
Stanislav Záliš, Jan Heyda, Filip Šebesta, Jay R. Winkler, Harry B. Gray, Antonı́n Vlček
Abstract
Significance Electron (hole) hopping through tryptophan residues activates protein cofactors, participates in cellular photosignaling, and protects enzymes from oxidative degradation. The energetics of excited chromophores, together with their positions relative to proximal indoles, are evolution-optimized in natural photolyases and cryptochromes. Our theoretical analysis of photoinduced hole hopping through tryptophans in rhenium-modified blue copper proteins has shed light on the roles of electronic coupling and adiabaticity, as well as electrostatic-field fluctuations and solvation dynamics in driving charge transport rapidly over long distances. The take-home message is that attention should be paid to solvation of redox-active molecules in hopping chains in the design of bioinspired light-harvesting systems and functional photocatalysts.