Novel statistical-thermodynamic method for computation of protein-ligand binding entropy: Docking tests with 11 scoring functions

COMP 108

Anatoly M. Ruvinsky, ruvinsky@ku.edu, Center for Bioinformatics, The University of Kansas, 2030 Becker Drive, Lawrence, KS 66047
We present results of testing of the ability of eleven popular scoring functions to predict native docked positions using a recently developed method [1,2] for estimation the entropy contributions of relative and torsional motions to protein-ligand binding affinity. The method is based on the Monte-Carlo integration of the configurational integral over clusters obtained from multiple docked positions. We use a test set of 100 PDB protein-ligand complexes and ensembles of 101 docked positions generated by Wang et al [3] for each ligand in the test set. To test the suggested method we compare the averaged root-mean square deviations (RMSD) of the top-scored ligand docked positions, accounting and not accounting for entropy contributions, relative to the experimentally determined positions. We demonstrate that the method increases docking accuracy by 10-21% when used in conjunction with the AutoDock scoring function, by 2-25% with G-Score, by 7-41% with D-Score, by 0-8% with LigScore, by 1-6% with PLP, by 0-12% with LUDI, by 2-8% with F-Score, by 7-29% with ChemScore, by 0-9% with X-Score, by 2-19% with PMF, and by 1-7% with DrugScore. We also compare the performance of the suggested method with the method based on ranking by cluster occupancy only. We analyze how the choice of a RMSD-tolerance and a low bound of dense clusters impacts on docking accuracy of the scoring methods. We derive optimal intervals of the RMSD-tolerance for 11 scoring functions.

1. Ruvinsky A.M. submitted, 2006.

2. Ruvinsky AM, Kozincev AV. J Comp Chem 2005; 26: 1089-1095.

3. Wang R, Lu Y, Wang S. J Med Chem 2003; 46: 2287- 2303.