Irbäck A, Sjunnesson F, Wallin S
Complex Systems Division, Department of Theoretical Physics, Lund University, Sölvegatan 14A, S-223 62 Lund, Sweden.
Proc Natl Acad Sci U S A. 2000 Dec 5;97(25):13614-8. doi: 10.1073/pnas.240245297.
We study the thermodynamic behavior of a model protein with 54 amino acids that forms a three-helix bundle in its native state. The model contains three types of amino acids and five to six atoms per amino acid and has the Ramachandran torsional angles phi(i), psi(i) as its degrees of freedom. The force field is based on hydrogen bonds and effective hydrophobicity forces. For a suitable choice of the relative strength of these interactions, we find that the three-helix-bundle protein undergoes an abrupt folding transition from an expanded state to the native state. Also shown is that the corresponding one- and two-helix segments are less stable than the three-helix sequence.
我们研究了一种由54个氨基酸组成的模型蛋白质的热力学行为，该蛋白质在其天然状态下形成三螺旋束。该模型包含三种类型的氨基酸，每个氨基酸有五到六个原子，并以拉马钱德兰扭转角phi(i)、psi(i)作为其自由度。力场基于氢键和有效的疏水力。对于这些相互作用相对强度的合适选择，我们发现三螺旋束蛋白质经历了从伸展状态到天然状态的突然折叠转变。还表明，相应的单螺旋和双螺旋片段比三螺旋序列稳定性更低。
