Experimental tests of villin subdomain folding simulations
Experimental tests of villin subdomain folding simulations
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DOI：
10.1016/s0022-2836(03)00519-9
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发表时间：
2003-06-13
影响因子：
5.6
通讯作者：
Hofrichter, J
中科院分区：
文献类型：
--
作者：
Kubelka, J;Eaton, WA;Hofrichter, J
我们用激光温度跳跃法研究了绒毛蛋白头部35个残基亚结构域的折叠动力学和机制。松弛动力学是双相的，具有对应于螺旋-卷曲转变的亚微秒相和对应于整体展开/重折叠的较慢微秒相。在300 K时，折叠时间为4.3（+/- 0.6）μ s，使其成为折叠速度最快的天然蛋白质，其速率接近理论速度极限。这一时间与Zagrovic等人使用隐式溶剂模型从原子分子动力学模拟中预测的5（+11，-3）μ s非常一致。我们测试了他们的预测，即用丙氨酸替换C-末端苯丙氨酸残基将通过去除瞬时非天然相互作用来增加折叠速率。我们发现丙氨酸取代对折叠速率和平衡常数没有影响。这一结果的有效性的模拟折叠机制的影响进行了讨论。爱思唯尔科技有限公司出版
We have used laser temperature-jump to investigate the kinetics and mechanism of folding the 35 residue subdomain of the villin headpiece. The relaxation kinetics are biphasic with a sub-microsecond phase corresponding to a helix-coil transition and a slower microsecond phase corresponding to overall unfolding/refolding. At 300 K, the folding time is 4.3(+/- 0.6) mus, making it the fastest folding, naturally occurring protein, with a rate close to the theoretical speed limit. This time is in remarkable agreement with the prediction of 5 (+11, - 3) mus by Zagrovic et al. from atomistic molecular dynamics simulations using an implicit solvent model. We test their prediction that replacement of the C-terminal phenylalanine residue with alanine will increase the folding rate by removing a transient non-native interaction. We find that the alanine substitution has no effect on the folding rate or on the equilibrium constant. Implications of this result for the validity of the simulated folding mechanism are discussed. Published by Elsevier Science Ltd.