Lim M, Jackson T A, Anfinrud P A
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Nat Struct Biol. 1997 Mar;4(3):209-14. doi: 10.1038/nsb0397-209.
The nature of ligand motion within proteins has been investigated by measuring femtosecond time-resolved infrared (IR) spectra of CO photodissociated from the haem of myoglobin. Upon dissociation, the CO rotates approximately 90 degrees and becomes trapped within a ligand docking site located near the binding site. Two trajectories, distinguished spectroscopically and kinetically with time constants of 0.20 +/- 0.05 ps and 0.52 +/- 0.10 ps, lead to CO located within the docking site with opposite orientations. The protein reorganizes about the "docked' CO with a time constant of 1.6 +/- 0.3 ps and quickly establishes an energetic barrier that inhibits the reverse rebinding process.
通过测量从肌红蛋白血红素中光解离的一氧化碳（CO）的飞秒时间分辨红外（IR）光谱，研究了蛋白质中配体运动的性质。解离后，CO旋转约90度，并被困在位于结合位点附近的配体对接位点内。两条轨迹在光谱和动力学上有所区分，时间常数分别为0.20±0.05皮秒和0.52±0.10皮秒，导致CO以相反的方向位于对接位点内。蛋白质围绕“对接”的CO重新组织，时间常数为1.6±0.3皮秒，并迅速建立起一个能量屏障，抑制反向再结合过程。
