Chapagain Prem P, Liu Yanxin, Gerstman Bernard S
Department of Physics, Florida International University, University Park, Miami, Florida 33199, USA.
J Chem Phys. 2008 Nov 7;129(17):175103. doi: 10.1063/1.3006421.
We investigate the importance of the trigger sequence in the folding and dimerization of the GCN4 leucine zipper. We examine the role of the enhanced propensity of the amino acids in the trigger sequence to form an alpha-helix. Using computer simulations, we calculate heat capacities, free energy profiles, and the probability for successful dimerization as a function of the strength of the alpha-helical propensity of the trigger sequence. Our results elucidate the experimentally observed importance of the trigger sequence for dimerization and why it is not necessary for the trigger to have a specific "consensus" sequence of amino acids. We also find that a stronger trigger sequence not only increases the probability for dimerization but also changes the dimerization dynamics by introducing multiple intermediate states.
我们研究了触发序列在GCN4亮氨酸拉链折叠和二聚化过程中的重要性。我们考察了触发序列中氨基酸形成α-螺旋倾向增强的作用。通过计算机模拟，我们计算了热容量、自由能分布以及成功二聚化的概率，这些都是触发序列α-螺旋倾向强度的函数。我们的结果阐明了实验观察到的触发序列对二聚化的重要性，以及为什么触发序列没有特定的氨基酸“共有”序列也没有必要。我们还发现，更强的触发序列不仅增加了二聚化的概率，还通过引入多个中间状态改变了二聚化动力学。
