Sreerama N, Woody R W
Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins 80523.
Biochemistry. 1994 Aug 23;33(33):10022-5. doi: 10.1021/bi00199a028.
A method to identify poly(L-proline)-type (PII) conformation in crystal structures of globular proteins is presented. Short segments of PII structure were identified in globular protein structures, and these form a significant fraction of the residues which are not assigned to alpha-helix, beta-sheet, and beta-turns. The fractions of alpha-helix, beta-sheet, beta-turns, PII, and unordered, identified in conjunction with the Kabsch and Sander method [(1983) Biopolymers 22, 2577], were incorporated in the analysis of circular dichroism (CD) spectra of proteins. The separation of PII fraction from the fraction of residues not assigned to alpha-helix or beta-sheet or -turns resulted in a distinctive PII CD spectrum and an unusual CD spectrum corresponding to the residual unassigned structures. The quality of prediction of PII fraction from CD spectra of proteins was comparable to that of beta-sheet and -turns.
本文提出了一种在球状蛋白质晶体结构中识别聚（L-脯氨酸）型（PII）构象的方法。在球状蛋白质结构中识别出了PII结构的短片段，这些片段构成了未被指定为α-螺旋、β-折叠和β-转角的残基的很大一部分。结合卡布斯和桑德方法[（1983年）《生物聚合物》22，2577]确定的α-螺旋、β-折叠、β-转角、PII和无序部分，被纳入蛋白质圆二色性（CD）光谱分析中。将PII部分与未被指定为α-螺旋、β-折叠或β-转角的残基部分分离，得到了独特的PII CD光谱和对应于残留未指定结构的异常CD光谱。从蛋白质CD光谱预测PII部分的质量与β-折叠和β-转角的预测质量相当。
