典型蛋白质折叠中阳离子-π相互作用的特异性

Specificity of Cation-π Interactions in Typical Protein Folds

蛋白质中的阳离子-π相互作用是带正电荷的氨基酸(Lys、Arg)和芳香族氨基酸(Phe、Tyr、Trp)之间的一种作用力.对α/β类蛋白中两种典型折叠类型(单绕和双绕)的研究表明:(1)单绕结构中阳离子-π相互作用的分布密度大约是双绕结构中的2.6倍;(2)在单绕结构中,样本所含氨基酸残基数量与样本中阳离子-π的数量有明显的相关性,在双绕结构中没有发现类似的相关性;(3)Lys、Arg与Tyr在单绕中比在双绕中更容易形成阳离子-π相互作用;(4)Arg-Tyr组合在单绕中出现的几率较大,Arg-Phe组合在双绕中出现的几率较大;(5)阳离子-π相互作用在65%的单绕样本中形成阵列或分布在结构的首尾间.

In proteins,cation-π interactions are formed between positively charged amino acids（Lys,Arg） and aromatic amino acids（Phe,Tyr,Trp）.We investigated the cation-π interactions in two typical folding structures of α/β proteins,namely,the singly wound structure and the doubly wound structure.The results reveal that：（1） The distribution density of cation-π interactions in singly wound structures is about 2.6 times as high as that in doubly wound structures;（2） In singly wound structures,a correlation is observed between the amount of residues and their cation-π interactions while no correlation is observed in doubly wound structures;（3） Lys,Arg and Tyr in singly wound structures participate more easily in cation-π interactions than those in doubly wound structures;（4） Arg-Phe pairs are preferred in doubly wound structures while Arg-Tyr pairs are preferred in singly wound structures;（5） In singly wound structures,65% of the cation-π interactions form arrays or distribute between the starting point and the end point in the structures.