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arXiv 1301.4564q-bio.BM
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配体结合后的蛋白质柔性:对接预测和统计分析

Protein flexibility upon ligand binding: Docking predictions and statistical analysis

Rafael Najmanovich

摘要:

侧链柔性是配体结合的重要因素。为了确定侧链柔性参与配体结合的程度,采用了基于知识的方法。由存在或不存在给定配体的蛋白质结构的实例组成的数据库用于分析哪些侧链经历侧链构象变化。这样的分析已经确定高达40%的结合位点不存在侧链构象变化。总共有三个残基发生侧链构象变化,包括约85%的结合位点的研究。当分析不同氨基酸经历侧链构象变化的倾向时,我们发现不同氨基酸之间存在相当大的差异。使用支持向量机器学习方法来创建分类器系统,该分类器系统利用关于溶剂可及面积以及待预测的每个特定侧链及其相邻侧链的柔性尺度值的信息。使用这种方法可以达到70%的准确度。在大多数结合位点中少数残基经历侧链构象变化的事实使得在对接模拟中引入侧链柔性是可行的。已经开发了一种算法,用于引入侧链的灵活性,利用混合遗传算法/穷举搜索过程和基于表面互补性的评分函数。这种方法在软件工具FlexAID中实现。FlexAID利用旋转异构体库为对接模拟期间彻底搜索的残基列表创建替代构象。FlexAID在刚性局部和全局模拟中的性能在局部和全局模拟的70-80%范围内。

英文摘要:

Side chain flexibility is an important factor in ligand binding. In order to determine the extent to which side chain flexibility is involved in ligand binding, a knowledge-based approach was taken. A database composed of examples of protein structures in the presence or absence of a given ligand is used to analyze which side chains undergo side chain conformational changes. Such an analysis has determined that up to 40% of binding site do not present side chain conformational changes. A total of three residues undergoing side chain conformational changes encompass approximately 85% of the binding sites studied. When analyzing the propensities of different amino acids to undergo side chain conformational changes we find that there are considerable differences between different amino acids. A support vector machine learning approach was used to create a classifier system utilizing information about the solvent accessible area as well as flexibility scale value of each specific side chain to be predicted together with its neighboring side chains. An accuracy level of 70% is reached using this approach. The fact that a small number of residues undergo side chain conformational changes in the majority of binding sites makes it feasible to introduce side chain flexibility in docking simulations. An algorithm has been developed for introducing side chain flexibility utilizing a hybrid genetic-algorithm/exhaustive-search procedure and a surface complementarity based scoring function. This approach is implemented in the software tool FlexAID. FlexAID utilizes a rotamer library to create alternative conformations for a list of residues that are exhaustively searched during the docking simulation. The performance of FlexAID in rigid local as well as global simulations falls in the 70-80% range for both local and global simulations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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