Carlier M F, Hill T L, Chen Y
Proc Natl Acad Sci U S A. 1984 Feb;81(3):771-5. doi: 10.1073/pnas.81.3.771.
This paper reports an experimental study of the interference of GTP hydrolysis in the mechanism of microtubule assembly, following the model and theory previously published [Hill, T. L. & Carlier, M.-F. (1983) Proc. Natl. Acad. Sci. USA 80, 7234-7238]. Results from dilution experiments show that microtubules depolymerize faster below the critical concentration than expected with a reversible polymerization model. The experimental plot of flux versus tubulin concentration exhibits a slope discontinuity at the critical concentration, in agreement with the theory. Theoretical points calculated by the Monte Carlo method can be fitted qualitatively to the data. A consequence of this peculiar dynamic behavior of microtubules is that the ratio of tubulin dissociation and association rate constants measured, respectively, below and above the critical concentration does not yield the true value of the critical concentration. It is emphasized that the presence of GTP at microtubule ends is necessary to maintain the stability of the polymer.
本文依据先前发表的模型和理论[希尔,T. L. & 卡里尔,M.-F.(1983年)《美国国家科学院院刊》80,7234 - 7238],报告了一项关于GTP水解对微管组装机制干扰的实验研究。稀释实验结果表明,在临界浓度以下,微管解聚速度比可逆聚合模型预期的要快。通量与微管蛋白浓度的实验曲线在临界浓度处呈现斜率不连续,这与理论相符。通过蒙特卡罗方法计算的理论点可以定性地拟合数据。微管这种特殊动态行为的一个结果是,分别在临界浓度以下和以上测量的微管蛋白解离和缔合速率常数之比并不能得出临界浓度的真实值。需要强调的是,微管末端存在GTP对于维持聚合物的稳定性是必要的。