Differentiation of AmpC beta-lactamase binders vs. decoys using classification kNN QSAR modeling and application of the QSAR classifier to virtual screening
| Autor: | Xiang Simon Wang, Jui-Hua Hsieh, Alexander Tropsha, Alexander Golbraikh, Denise G. Teotico |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular Quantitative structure–activity relationship Databases Factual Quantitative Structure-Activity Relationship AmpC beta-lactamase Computational biology Machine learning computer.software_genre Binding Competitive beta-Lactamases Bacterial Proteins Predictive Value of Tests Drug Discovery Combinatorial Chemistry Techniques Computer Simulation Physical and Theoretical Chemistry Enzyme Inhibitors Beta-Lactamase Inhibitors Virtual screening Molecular Structure Chemistry business.industry Computer Science Applications Docking (molecular) Drug Design Artificial intelligence business beta-Lactamase Inhibitors computer Classifier (UML) PubChem Algorithms Software Applicability domain |
| Zdroj: | Journal of computer-aided molecular design. 22(9) |
| ISSN: | 0920-654X |
| Popis: | The use of inaccurate scoring functions in docking algorithms may result in the selection of compounds with high predicted binding affinity that nevertheless are known experimentally not to bind to the target receptor. Such falsely predicted binders have been termed 'binding decoys'. We posed a question as to whether true binders and decoys could be distinguished based only on their structural chemical descriptors using approaches commonly used in ligand based drug design. We have applied the k-Nearest Neighbor (kNN) classification QSAR approach to a dataset of compounds characterized as binders or binding decoys of AmpC beta-lactamase. Models were subjected to rigorous internal and external validation as part of our standard workflow and a special QSAR modeling scheme was employed that took into account the imbalanced ratio of inhibitors to non-binders (1:4) in this dataset. 342 predictive models were obtained with correct classification rate (CCR) for both training and test sets as high as 0.90 or higher. The prediction accuracy was as high as 100% (CCR = 1.00) for the external validation set composed of 10 compounds (5 true binders and 5 decoys) selected randomly from the original dataset. For an additional external set of 50 known non-binders, we have achieved the CCR of 0.87 using very conservative model applicability domain threshold. The validated binary kNN QSAR models were further employed for mining the NCGC AmpC screening dataset (69653 compounds). The consensus prediction of 64 compounds identified as screening hits in the AmpC PubChem assay disagreed with their annotation in PubChem but was in agreement with the results of secondary assays. At the same time, 15 compounds were identified as potential binders contrary to their annotation in PubChem. Five of them were tested experimentally and showed inhibitory activities in millimolar range with the highest binding constant K(i) of 135 microM. Our studies suggest that validated QSAR models could complement structure based docking and scoring approaches in identifying promising hits by virtual screening of molecular libraries. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink