STOCHASTIC SIMULATION OF ACTIVATION IN THE G-PROTEIN CASCADE OF PHOTOTRANSDUCTION
STOCHASTIC SIMULATION OF ACTIVATION IN THE G-PROTEIN CASCADE OF PHOTOTRANSDUCTION
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DOI：
10.1016/s0006-3495(94)80617-4
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发表时间：
1994-10-01
影响因子：
3.4
通讯作者：
LAMB, TD
中科院分区：
文献类型：
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作者：
LAMB, TD
通过模拟视紫红质(R(*))、G蛋白(G)和效应蛋白(E，磷酸二酯酶，PDE)这三种反应蛋白在视紫红质(R(*))、G蛋白(G)和效应蛋白(E，磷酸二酯酶，PDE)之间的二维扩散相互作用，模拟了光转导下G蛋白级联的激活。随机模拟证实了简化分析模型的主要预测(Lamb，T.D.和E.N.Pugh，1992，Journal of Physiology 449：719-758)，并将这种处理扩展到更复杂的情况，其中反应的概率有限或反应时间有限。模拟还根据参与分子的浓度、侧向扩散系数和结合速率常数，定量估计了从激活的G蛋白(G(*))到激活的效应器(E(*))的偶联效率；从G(*)到E(*)的偶联效率并不像以前的简化分析理论中那样高。这一发现可以推广到其他G蛋白级联，只要这些级联的物理参数得到指定。
Activation of the G-protein cascade underlying phototransduction has been modeled by simulating the two-dimensional diffusional interactions that occur at the rod disc membrane between the three reacting protein species, which are the activated rhodopsin (R(*)), the G-protein (G), and the effector protein (E, the phosphodiesterase, PDE). The stochastic simulations confirm the main predictions of a simplified analytical model (Lamb, T. D., and E. N. Pugh, 1992, Journal of Physiology 449:719-758), and extend that treatment to more complicated cases, where there is a finite probability of reaction or a finite time for reaction. The simulations also provide quantitative estimates of the efficiency of coupling from activated G-protein (G(*)) to activated effector (E(*)) in terms of the concentrations, lateral diffusion coefficients, and binding rate constants of the participating molecules; the efficiency of coupling from G(*) to E(*) is found to be not as high as in the previous simplified analytical theory. The findings can be extended to other G-protein cascades, provided that the physical parameters of those cascades are specified.