Bhagwat Medha, Aravind L
National Center for Biotechnology, Information, National Library of Medicine, National Institutes of Health, USA.
Methods Mol Biol. 2007;395:177-86. doi: 10.1007/978-1-59745-514-5_10.
PSI-BLAST (Position-Specific Iterative Basic Local Alignment Search Tool) derives a position-specific scoring matrix (PSSM) or profile from the multiple sequence alignment of sequences detected above a given score threshold using protein-protein BLAST. This PSSM is used to further search the database for new matches, and is updated for subsequent iterations with these newly detected sequences. Thus, PSI-BLAST provides a means of detecting distant relationships between proteins. In this chapter, we discuss practical aspects of using PSI-BLAST and provide a tutorial on how to uncover distant relationships between proteins and use them to reach biologically meaningful conclusions.
PSI-BLAST（位置特异性迭代基本局部比对搜索工具）使用蛋白质-蛋白质BLAST从高于给定得分阈值检测到的序列的多序列比对中导出位置特异性评分矩阵（PSSM）或轮廓。该PSSM用于进一步搜索数据库以寻找新的匹配项，并随着这些新检测到的序列在后续迭代中进行更新。因此，PSI-BLAST提供了一种检测蛋白质之间远缘关系的方法。在本章中，我们将讨论使用PSI-BLAST的实际方面，并提供一个教程，说明如何揭示蛋白质之间的远缘关系并利用它们得出具有生物学意义的结论。
