The Brownian ratchet and power stroke models for posttranslational protein translocation into the endoplasmic reticulum
The Brownian ratchet and power stroke models for posttranslational protein translocation into the endoplasmic reticulum
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DOI：
10.1016/s0006-3495(02)75480-5
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发表时间：
2002-03-01
影响因子：
3.4
通讯作者：
Elston, TC
中科院分区：
文献类型：
--
作者：
Elston, TC
对翻译后移位到内质网的实验数据进行了定量分析。这一分析表明，易位涉及单个速率限制步骤，该步骤被假定为从易位通道释放信号序列。接下来，将布朗棘轮模型和权力行程移位模型与数据进行比较。使用最小二乘准则同时对数据集进行拟合，发现两个模型都能准确地再现实验结果。似然比检验表明，布朗棘轮模型的最优拟合度与功率冲程模型的最优拟合度没有显著差异，该模型只包含一个自由参数。因此，这里考虑的数据不能用来拒绝这种进口机制。使用估计的参数对模型进行进一步分析，以进行实验可检验的预测。
A quantitative analysis of experimental data for posttranslational translocation into the endoplasmic reticulum is performed. This analysis reveals that translocation involves a single rate-limiting step, which is postulated to be the release of the signal sequence from the translocation channel. Next, the Brownian ratchet and power stroke models of translocation are compared against the data. The data sets are simultaneously fit using a least-squares criterion, and both models are found to accurately reproduce the experimental results. A likelihood-ratio test reveals that the optimal fit of the Brownian ratchet model, which contains one fewer free parameter, does not differ significantly from that of the power stroke model. Therefore, the data considered here cannot be used to reject this import mechanism. The models are further analyzed using the estimated parameters to make experimentally testable predictions.