title: Predicting protein conformational changes for unbound and homology docking: learning from intrinsic and induced flexibility.
abstract: Predicting protein conformational changes from unbound structures or even homology models to bound structures remains a critical challenge for protein docking. Here we present a study directly addressing the challenge by reducing the dimensionality and narrowing the range of the corresponding conformational space. The study builds on cNMA-our new framework of partner- and contact-specific normal mode analysis that exploits encounter complexes and considers both intrinsic and induced flexibility. First, we established over a CAPRI (Critical Assessment of PRedicted Interactions) target set that the direction of conformational changes from unbound structures and homology models can be reproduced to a great extent by a small set of cNMA modes. In particular, homology-to-bound interface root-mean-square deviation (iRMSD) can be reduced by 40% on average with the slowest 30 modes. Second, we developed novel and interpretable features from cNMA and used various machine learning approaches to predict the extent of conformational changes. The models learned from a set of unbound-to-bound conformational changes could predict the actual extent of iRMSD with errors around 0.6 Å for unbound proteins in a held-out benchmark subset, around 0.8 Å for unbound proteins in the CAPRI set, and around 1 Å even for homology models in the CAPRI set. Our results shed new insights into origins of conformational differences between homology models and bound structures and provide new support for the low-dimensionality of conformational adjustment during protein associations. The results also provide new tools for ensemble generation and conformational sampling in unbound and homology docking. Proteins 2017; 85:544-556. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843.
authors.forename: Haoran
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843.
authors.forename: Yuanfei
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843.|TEES-AgriLife Center for Bioinformatics and Genomic Systems Engineering, Texas A&M University, College Station, Texas, 77843.
authors.forename: Yang
authors.identifier: 0000-0002-1703-7796
authors.initials: Y
authors.lastname: Shen
mesh_terms: D019985:Benchmarking; D001665:Binding Sites; D019295:Computational Biology / Q000379:methods*; D061827:Dimensional Measurement Accuracy; D000069550:Machine Learning; D015233:Models, Statistical; D062105:Molecular Docking Simulation / Q000379:methods*; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D011506:Proteins / Q000737:chemistry*; D012107:Research Design; D012984:Software; D040681:Structural Homology, Protein; D013816:Thermodynamics
chemical_list: D011506:Proteins
keywords: conformational change; conformational selection; homology model; induced fit; induced flexibility; intrinsic flexibility; machine learning; normal mode analysis; protein docking