title: Physical binding pocket induction for affinity prediction.
abstract: Computational methods for predicting ligand affinity where no protein structure is known generally take the form of regression analysis based on molecular features that have only a tangential relationship to a protein/ligand binding event. Such methods have limited utility when structural variation moves beyond congeneric series. We present a novel approach based on the multiple-instance learning method of Compass, where a physical model of a binding site is induced from ligands and their corresponding activity data. The model consists of molecular fragments that can account for multiple positions of literal protein residues. We demonstrate the method on 5HT1a ligands by training on a series with limited scaffold variation and testing on numerous ligands with variant scaffolds. Predictive error was between 0.5 and 1.0 log units (0.7-1.4 kcal/mol), with statistically significant rank correlations. Accurate activity predictions of novel ligands were demonstrated using a validation approach where a small number of ligands of limited structural variation known at a fixed time point were used to make predictions on a blind test set of widely varying molecules, some discovered at a much later time point.
authors.affiliation: Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158-9001, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Langham
authors.forename: Ann E
authors.initials: AE
authors.lastname: Cleves
authors.forename: Russell
authors.initials: R
authors.lastname: Spitzer
authors.forename: Daniel
authors.initials: D
authors.lastname: Kirshner
authors.forename: Ajay N
authors.initials: AN
authors.lastname: Jain
mesh_terms: D001665:Binding Sites; D008024:Ligands; D008958:Models, Molecular; D016571:Neural Networks, Computer; D010446:Peptide Fragments; D011485:Protein Binding; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism*
chemical_list: D008024:Ligands; D010446:Peptide Fragments; D044282:Receptor, Serotonin, 5-HT1A