Multi-step rhodopsin inactivation schemes can account for the size variability of single photon responses in Limulus ventral photoreceptors.
Multi-step rhodopsin inactivation schemes can account for the size variability of single photon responses in Limulus ventral photoreceptors.
复制标题
多步视紫红质失活方案可以解释鲎腹侧光感受器中单光子响应的大小变异性。
DOI：
10.1085/jgp.103.4.691
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Lisman,JE
中科院分区：
文献类型：
--
作者：
Goldring,MA;Lisman,JE
鲎腹侧光感受器对单个光子的吸收产生高度可变的反应。我们已经获得了这些响应的大小分布的数据，从简单的转导级联模型预测的分布，并比较了理论和数据。在最简单的模型中，视色素的活性状态（由其激活G蛋白的能力定义）在单个反应中被关闭。这种级联的输出预计是高度可变的，主要是因为G蛋白激活数量的随机变化。预测的确切分布是指数分布，但我们发现指数分布并不能充分解释数据。这些数据与级联模型的预测吻合得更好，在级联模型中，视觉色素的活性状态是通过多步过程关闭的。
Limulus ventral photoreceptors generate highly variable responses to the absorption of single photons. We have obtained data on the size distribution of these responses, derived the distribution predicted from simple transduction cascade models and compared the theory and data. In the simplest of models, the active state of the visual pigment (defined by its ability to activate G protein) is turned off in a single reaction. The output of such a cascade is predicted to be highly variable, largely because of stochastic variation in the number of G proteins activated. The exact distribution predicted is exponential, but we find that an exponential does not adequately account for the data. The data agree much better with the predictions of a cascade model in which the active state of the visual pigment is turned off by a multi-step process.