Michal Ben-Nun, Ferenc Molnar, Hui Lu, James C. Phillips, Todd J.
Martínez, and Klaus Schulten.
Quantum dynamics of retinal's femtosecond photoisomerization in
bacteriorhodopsin.
In Faraday Discussions, No. 110, pp. 447-462. Faraday
Publications, 1998.
BENN98
The membrane protein bacteriorhodopsin contains all- retinal in a binding site lined by amino acid side groups and water molecules that guide retinal's photodynamics. Upon absorption of light, retinal undergoes a sub-picosecond all-
13- phototransformation involving torsion around a double bond. The main reaction product triggers later events in the protein that induce pumping of a proton through bacteriorhodopsin. Quantum-chemical calculations suggest that three coupled electronic states, the ground state and two closely lying excited states, are involved in the motion along the torsional reaction coordinate . The evolution of the protein-retinal system on these three electronic surfaces has been modeled using the multiple spawning method for non-adiabatic dynamics. We find that although most of the population transfer occurs on a time scale of 300 fs, some population transfer occurs on a longer time scale, occasionally extending well beyond 1 ps. The simulations predict that the photoisomerization quantum yield is 48%, in reasonable accord with experimental observation.
Download Full Text
The manuscripts available on our site are provided for your personal
use only and may not be retransmitted or redistributed without written
permissions from the paper's publisher and author. You may not upload any
of this site's material to any public server, on-line service, network, or
bulletin board without prior written permission from the publisher and
author. You may not make copies for any commercial purpose. Reproduction
or storage of materials retrieved from this web site is subject to the
U.S. Copyright Act of 1976, Title 17 U.S.C.