Xu D, Martin C, Schulten K
Beckman Institute, University of Illinois at Urbana-Champaign 61801, USA.
Biophys J. 1996 Jan;70(1):453-60. doi: 10.1016/S0006-3495(96)79588-7.
Molecular dynamics simulations have been carried out to study the J625 and K590 intermediates of bacteriorhodopsin's (bRs) photocycle starting from a refined structure of bR568. The coupling between the electronic states of retinal and the protein matrix is characterized by the energy difference delta E(t) between the excited state and the ground state to which the protein contributes through the Coulomb interaction. Our simulations indicate that the J625 intermediate is related to a polarization of the protein matrix due to the brief (200 fs) change of retinal's charge distribution in going to the excited state and back to the ground state, and that the rise time of the K590 intermediate is determined by vibrational cooling of retinal.
已开展分子动力学模拟，从细菌视紫红质（bR）568的精细结构出发，研究细菌视紫红质光循环的J625和K590中间体。视黄醛电子态与蛋白质基质之间的耦合由激发态与基态之间的能量差ΔE(t)表征，蛋白质通过库仑相互作用对该能量差有贡献。我们的模拟表明，J625中间体与蛋白质基质的极化有关，这是由于视黄醛电荷分布在进入激发态并回到基态时发生短暂（200飞秒）变化所致，并且K590中间体的上升时间由视黄醛的振动冷却决定。
