Sun Z, Jiang B
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China.
J Protein Chem. 1996 Oct;15(7):675-90. doi: 10.1007/BF01886750.
Short peptides connecting alpha-helices and beta-strands have been analyzed in 240 proteins refined at resolutions of 0.25 nm or better. Connecting peptides of lengths between one and five residues have been classified as part of supersecondary motifs of four types: alpha alpha, alpha beta, beta alpha, and beta beta. Careful consideration has been given to the definition of secondary structures on the basis of hydrogen bonds and main-chain conformational angles. Using five classes of residue conformation-a, b, e, l, t-in the nonregular structure regions of phi, psi space, 34 classes of supersecondary motifs occurring at least five times have been identified. Among these 34 classes, 11 classes that occur more than 25 times are commonly occurring supersecondary structure motifs. The patterns and conformations of the 11 commonly occurring supersecondary structure motifs have been characterized, demonstrating that patterns and conformations adopted by supersecondary structure motifs are limited. The results have relevance to structure prediction, comparative modeling, and protein folding.
在240种分辨率达到或优于0.25纳米的精制蛋白质中，对连接α螺旋和β链的短肽进行了分析。长度在1至5个残基之间的连接肽已被归类为四种超二级基序的一部分：αα、αβ、βα和ββ。基于氢键和主链构象角，对二级结构的定义进行了仔细考量。利用φ、ψ空间非规则结构区域中的五类残基构象——a、b、e、l、t，已识别出至少出现五次的34类超二级基序。在这34类中，出现超过25次的11类是常见的超二级结构基序。已对这11种常见超二级结构基序的模式和构象进行了表征，表明超二级结构基序所采用的模式和构象是有限的。这些结果与结构预测、比较建模和蛋白质折叠相关。
