Brünger A T, Clore G M, Gronenborn A M, Karplus M
Department of Chemistry, Harvard University, Cambridge, MA 02138.
Protein Eng. 1987 Oct-Nov;1(5):399-406. doi: 10.1093/protein/1.5.399.
A series of three-dimensional structures of the 1-29 fragment of human growth hormone releasing factor in trifluoroethanol have been determined by molecular dynamics and distance geometry methods. The resulting structures satisfy information from nuclear Overhauser effect (NOE) distance data and an empirical potential energy function. Although the polypeptide was found to have an ordered structure in all simulations, the NOE data were not sufficient for global convergence to a unique three-dimensional geometry. Several satisfactory structures have been determined, all of which are extended conformations consisting of a short beta-strand and two alpha-helices (residues 6-13 and residues 16-29) connected by short segments of less well defined secondary structure. Because of the lack of NOE data connecting the helix segments, their relative orientation is not uniquely determined.
通过分子动力学和距离几何方法，已确定了人生长激素释放因子1 - 29片段在三氟乙醇中的一系列三维结构。所得结构符合来自核Overhauser效应（NOE）距离数据和经验势能函数的信息。尽管在所有模拟中发现该多肽具有有序结构，但NOE数据不足以全局收敛到唯一的三维几何结构。已确定了几个令人满意的结构，所有这些结构都是由短β链和两个α螺旋（残基6 - 13和残基16 - 29）组成的伸展构象，它们由定义不太明确的二级结构的短片段连接。由于缺乏连接螺旋段的NOE数据，它们的相对取向无法唯一确定。
