Lewis P N, Go N, Go M, Kotelchuck D, Scheraga H A
Proc Natl Acad Sci U S A. 1970 Apr;65(4):810-5. doi: 10.1073/pnas.65.4.810.
The Zimm-Bragg formulation for the one-dimensional Ising model is applied to denatured proteins in order to compute helix probability profiles with different sigma and s parameters for the various amino acids; the latter are in principle determinable from melting curves for helix-coil transitions in random copolymers of amino acids. Using a tentative assignment of sigma and s values, we found a correlation for the propensity of a residue to be helical in the denatured protein and its occurrence in a helical region in the globular structure of the corresponding native protein. Thus, these incipient helical regions in the denatured chain may serve to nucleate the folding to form the native protein. Short-range interactions appear to determine the tendency for a residue to be helical or not, whereas long-range interactions may serve to carry out the nucleation and refolding processes.
将一维伊辛模型的齐姆-布拉格公式应用于变性蛋白质，以计算不同氨基酸的不同西格玛（sigma）和s参数下的螺旋概率分布；原则上，后者可从氨基酸无规共聚物中螺旋-线团转变的熔解曲线确定。通过对西格玛和s值的初步赋值，我们发现变性蛋白质中一个残基形成螺旋的倾向与其在相应天然蛋白质球状结构的螺旋区域中的出现情况之间存在相关性。因此，变性链中的这些初始螺旋区域可能有助于折叠成核以形成天然蛋白质。短程相互作用似乎决定了一个残基是否形成螺旋的倾向，而长程相互作用可能有助于进行成核和重折叠过程。
