Semi-supervised prediction of protein interaction sites from unlabeled sample information.
BACKGROUND
The recognition of protein interaction sites is of great significance in many biological processes, signaling pathways and drug designs. However, most sites on protein sequences cannot be defined as interface or non-interface sites because only a small part of protein interactions had been identified, which will cause the lack of prediction accuracy and generalization ability of predictors in protein interaction sites prediction. Therefore, it is necessary to effectively improve prediction performance of protein interaction sites using large amounts of unlabeled data together with small amounts of labeled data and background knowledge today.


RESULTS
In this work, three semi-supervised support vector machine-based methods are proposed to improve the performance in the protein interaction sites prediction, in which the information of unlabeled protein sites can be involved. Herein, five features related with the evolutionary conservation of amino acids are extracted from HSSP database and Consurf Sever, i.e., residue spatial sequence spectrum, residue sequence information entropy and relative entropy, residue sequence conserved weight and residual Base evolution rate, to represent the residues within the protein sequence. Then three predictors are built for identifying the interface residues from protein surface using three types of semi-supervised support vector machine algorithms.


CONCLUSION
The experimental results demonstrated that the semi-supervised approaches can effectively improve prediction performance of protein interaction sites when unlabeled information is involved into the predictors and one of them can achieve the best prediction performance, i.e., the accuracy of 70.7%, the sensitivity of 62.67% and the specificity of 78.72%, respectively. With comparison to the existing studies, the semi-supervised models show the improvement of the predication performance.
['Wang|Ye|Y|', 'Mei|Changqing|C|', 'Zhou|Yuming|Y|', 'Wang|Yan|Y|', 'Zheng|Chunhou|C|', 'Zhen|Xiao|X|', 'Xiong|Yan|Y|', 'Chen|Peng|P|', 'Zhang|Jun|J|', 'Wang|Bing|B|']
D000465:Algorithms D000595:Amino Acid Sequence D000596:Amino Acids D001669:Biochemical Phenomena D017124:Conserved Sequence D019277:Entropy D011506:Proteins D060388:Support Vector Machine
Protein interaction site Semi-supervised support vector machine Unlabeled information Conservative feature