Stereochemical criteria for polypeptide and protein chain conformations
Stereochemical criteria for polypeptide and protein chain conformations
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多肽和蛋白链构象的立体化学标准
DOI：
10.1007/bf03046447
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发表时间：
1964
期刊：
影响因子：
--
通讯作者：
C. Ramakrishnan
中科院分区：
文献类型：
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作者：
C. Ramakrishnan
根据连接在α-碳原子上的两个肽基团的相对取向，多肽结构可能有许多构型。如果α-碳原子上的键是相同的，则结构呈现规则的螺旋形式。这种规则的螺旋结构可以用两个参数φ、φ′来描述，这两个参数是两个基团围绕在α-碳原子处相遇的N-αC和αC-C′键的旋转角。本文介绍了一种利用旋转矩阵计算结构螺旋参数的方法，即每圈的剩余数n，螺旋轴上的单位平移量沿着以及螺旋轴相对于适当选择的坐标系的方向余弦。对三种不同的角度值进行了评价
$$N\widehat{aC}C'$$
在α-碳原子上，即105°、110°和115°。结果在φ − φ′平面上以constantn和constanth曲线的形式图示。
SummaryA large number of configurations are possible for a polypeptide structure depending upon the relative orientations of the two peptide groups linked at anα-carbon atom. If the linkages at theα-carbon atoms are identical, then the structure assumes a regular helical form. Such a regular helical structure can be specified by two parametersφ, φ′ which are the angles of rotation of the two groups about the N—αC andαC—C′ bonds meeting at anα-carbon atom. In this paper, a method of evaluating the helical parameters of a structure, namely, the number of residues per turnn, the unit translation along the axis of the helixh and the direction cosines of the helical axis with respect to a suitably chosen co-ordinate system, is described making use of rotation matrices. The evaluation has been done for three different values of the angle
$$N\widehat{aC}C'$$
at theα-carbon atom, namely, 105°, 110° and 115°. The results are shown graphically in the form of curves for constantn and constanth in theφ − φ′ plane.