Reaction Dynamics of Halorhodopsin Studied by Time-Resolved Diffusion
Reaction Dynamics of Halorhodopsin Studied by Time-Resolved Diffusion
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DOI：
10.1016/j.bpj.2008.12.3932
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发表时间：
2009-05-06
影响因子：
3.4
通讯作者：
Terazima, Masahide
中科院分区：
文献类型：
--
作者：
Inoue, Keiichi;Kubo, Megumi;Terazima, Masahide
采用脉冲激光诱导瞬态光栅（TG）方法研究了法老碱单胞菌（Natronomonas pharaonis， N. pharaonis） （NpHR）氯离子泵蛋白halorhodopsin （HR）的反应动力学。对TG信号的详细研究表明，除了吸收-可观察的反应动力学外，还有一个谱上沉默的扩散过程。我们用Cl-离子的释放、扩散和吸收来解释这些动力学。通过对各种光栅波数信号的定量全局分析，得出Cl-离子的释放与L2 -> （L2（或N）可逆箭头O）过程有关，Cl-的吸收与（L2（或N）可逆箭头O） -> NpHR'过程有关。在循环反应过程中，NpHR在洗涤剂中的扩散系数没有变化。这一结果对比了许多光敏蛋白的行为，并表明从分子内到分子间氢键网络的变化对这种蛋白质泵的活性并不显著。
Reaction dynamics of a chloride ion pump protein, halorhodopsin (HR), from Natronomonas pharaonis (N. pharaonis) (NpHR) was studied by the pulsed-laser-induced transient grating (TG) method. A detailed investigation of the TG signal revealed that there is a spectrally silent diffusion process besides the absorption-observable reaction dynamics. We interpreted these dynamics in terms of release, diffusion, and uptake of the Cl- ion. From a quantitative global analysis of the signals at various grating wavenumbers, it was concluded that the release of the Cl- ion is associated with the L2 -> (L2 (or N) reversible arrow O) process, and uptake of Cl- occurs with the (L2 (or N) reversible arrow O) -> NpHR' process. The diffusion coefficient of NpHR solubilized in a detergent did not change during the cyclic reaction. This result contrasts the behavior of many photosensor proteins and implies that the change in the H-bond network from intra- to intermolecular is not significant for the activity of this protein pump.