提出了一种以残基间距离涨落为权重的氨基酸网络的加权方式.对180个蛋白质的加权与非加权氨基酸网络的拓扑特征量进行了分析.统计结果表明,氨基酸网络具有明显的小世界特征,加权网的平均集聚系数比非加权网的小.节点度分布具有幂律形式,显示了网络的层次模块性,进一步发现疏水残基对这一性质起了主要作用.另外,加权网的介数对折叠核的区分能力强于非加权网,表明加权网较非加权网包含了更多的蛋白质结构信息.
A method is proposed to construct the weighted amino acid network.The weight of link is based on the mean-square fluctuations of the distance of the contact residue pairs.For the 180 proteins with low homology,the small-world property is studied based on this method.The results show that the average clustering coefficients of the weighted networks are less than that of the unweighted networks.The power-law behavior of clustering coefficients of the weighted and the unweighted networks indicates that they have significant hierarchical structure,which mainly originates from the hierarchical behavior of the hydrophobic amino acid network.Finally,the comparison of the values calculated from the weighted network with that of the unweighted network shows that the weighted network has an obviously higher power to recognize the folding cores.These results reveal that the weighted amino acid network contains more information about amino acids than that of the unweighted network.