New antimicrobial drugs are urgently needed to tackle the emerging crisis of multidrug-resistant infections. We used high-throughput fragment screening to identify highly-ligandable target proteins, to improve the chances of delivering drugs with novel mechanisms of action. 50 potential targets were selected by bioinformatic analysis from a TraDIS dataset of essential genes. A high-throughput expression & purification platform was established to test the targets for expression. Biophysical techniques were used to QC 38 proteins & match them with a control ligand.
Proteins were screened against a library of 1280 fragments on a Biacore 8K, then hit fragments were confirmed in dose-response experiments. A Labcyte Echo 550 acoustic liquid handler was used to dispense all fragment solutions. This provided the necessary reproducibility between fragment screens and excellent solvent matching between sample injections and running buffer. For the dose-response experiments, hit fragments were cherry-picked directly from the screening plates, providing consistency between screening and follow-up experiments and simplifying compound handling.
Automated data-processing & machine learning were applied to assign a ligandability score to each target, prioritise hit fragments for progression, then compile a priority list of targets to advance. To automate plate handling and further enhance throughput, we have since augmented the Echo liquid handler with a Labcyte Access automation platform.
Peter Canning, LifeArc on behalf of Beckman Coulter