Photoinduced hole hopping through tryptophans in proteins

0541310 - ÚFCH JH 2022 RIV US eng J - Článek v odborném periodiku
Záliš, Stanislav - Heyda, Jan - Šebesta, F. - Winkler, J. R. - Gray, H. B. - Vlček, Antonín
Photoinduced hole hopping through tryptophans in proteins.
Proceedings of the National Academy of Sciences of the United States of America. Roč. 118, č. 11 (2021), č. článku e2024627118. ISSN 0027-8424. E-ISSN 1091-6490
Grant CEP: GA MŠMT(CZ) LTAUSA18026
Institucionální podpora: RVO:61388955
Klíčová slova: Azurin * Electron transfer * Hole hopping * Molecular dynamics * Tryptophan
Obor OECD: Physical chemistry
Impakt faktor: 12.779, rok: 2021
Způsob publikování: Omezený přístup

Hole hopping through tryptophan/tyrosine chains enables rapid unidirectional charge transport over long distances. We have elucidated structural and dynamical factors controlling hopping speed and efficiency in two modified azurin constructs that include a rhenium(I) sensitizer, Re(His)(CO)3(dmp)+, and one or two tryptophans (W1, W2). Experimental kinetics investigations showed that the two closely spaced (3 to 4 Å) intervening tryptophans dramatically accelerated long-range electron transfer (ET) from CuIto the photoexcited sensitizer. In our theoretical work, we found that time-dependent density-functional theory (TDDFT) quantum mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) trajectories of low-lying triplet excited states of ReI(His)(CO)3(dmp)+--W1(-W2) exhibited crossings between sensitizer-localized (∗Re) and charge-separated [ReI(His)(CO)3(dmp•-)/(W1•+or W2•+)] (CS1 or CS2) states. Our analysis revealed that the distances, angles, and mutual orientations of ET-active cofactors fluctuate in a relatively narrow range in which the cofactors are strongly coupled, enabling adiabatic ET. Waterdominated electrostatic field fluctuations bring ∗Re and CS1 states to a crossing where ∗Re(CO)3(dmp)+←W1ET occurs, and CS1 becomes the lowest triplet state. ET is promoted by solvation dynamics around ∗Re(CO)3(dmp)+(W1), and CS1 is stabilized by Re(dmp•-)/W1•+electron/hole interaction and enhanced W1•+solvation. The second hop, W1•+←W2, is facilitated by water fluctuations near the W1/W2unit, taking place when the electrostatic potential at W2drops well below that at W1•+. Insufficient solvation and reorganization around W2make W1•+←W2ET endergonic, shifting the equilibrium toward W1•+and decreasing the charge-separation yield. We suggest that multiscale TDDFT/ MM/MD is a suitable technique to model the simultaneous evolution of photogenerated excited-state manifolds.
Trvalý link: http://hdl.handle.net/11104/0318888