Our recent work in PNAS ‘Photoinduced hole hopping through tryptophans in proteins‘ presents a thorough investigation of water dynamics and electrostatic field fluctuations on the electron (hole) hopping dynamics in two rhenium-modified azurins. The research was done in collaboration with our excellent colleagues at Caltech, Queen Mary University of London, and Heyrovsky Institute of Czech Academy of Sciences.
We have employed QM/MM/MD TD-DFT dynamics on ps-timescales, which were complemented by advanced QM-analysis in the vicinity of electronic state crossing points. Accounting for explicit (MM) solvent we have described that the local hydration of key residues and ligands, which are involved in electron transport, fluctuates in time. Our results revealed that the electron hopping occurs, when the intrinsic hydration of TRP residue is not optimal for the initial electronic state, and instead resembles the hydration of the final state. Consequently, when the electron hop is attempted, the solvent environment is ready to stabilize it. In more generalized view, the electrostatic field fluctuations are good measures to judge if the system is approaching the electronic state crossing region.
Enjoy reading of our manuscript and if you are really interested check also our extensive SI.-)
Computer modeling of complex systems 