双绕蛋白质的分类与识别

蛋白质折叠识别是蛋白质结构研究的重要内容。双绕是α/β蛋白质中结构典型的常见折叠类型。选取22个家族中序列一致性小于25%的79个典型双绕蛋白质作为训练集,以RMSD为指标进行系统聚类,并对各类建立基于结构比对的概形隐马尔科夫模型(profile-HMM)。将Astral1.65中序列一致性小于95%的9 505个样本作为检验集,整体识别敏感性为93.9%,特异性为82.1%,MCC值为0.876。结果表明:对于成员较多,无法建立统一模型的折叠类型,分类建模可以实现较高准确率的识别。

Classification and recognition of Rossmann-fold protein

Fold recognition is an important issue in protein structure research. The Rossmann-fold protein that has typical structure is a common kind of α/β protein. The training set,selected from 22 families,is constituted of 79 Rossmann-fold proteins which have less than 25% sequence identity with each other.The hierarchical clustering method according to RMSD is applied and a profile-HMM based on structure alignment is built for each cluster. Testing on 9 505 proteins with less than 95% sequence identity from Astral1.65,the sensitivity,specificity and MCC are 93.9%,82.1% and 0.876 respectively. The result shows that building profile-HMMs after classification could reach precise fold recognition while a unified one cannot be built due to there are too many members in training set.