High-throughput Protein-Ligand Screening.

Overview
Applications

Currently, mass spectrometry (MS) based assays play a vital role within the drug development pipeline as both a method of screening potential ligands for protein binding and assessing relative or, in some cases, absolute binding strength of a protein-ligand complex. However, obtaining final confirmation of ligand binding and structural characterization data (at any level) on the newly-formed complex still remains a significant challenge. This situation frames a critical technology gap in the development phase of pharmaceuticals, where many potential drug candidates are screened by time-consuming or inefficient analytical methods leading to long lead compound development times and, eventually, cost inefficient pharmaceutical products. We are developing IM-MS-based protein ligand screening techniques that will enable the acquisition of both binding and structural information simultaneously. There are several different modes available to assess the consequences of small molecule bind with intact proteins using IM-MS screens (see publication 65 and the Figure on this page). IM data for mass-resolved ligand bound species can provide clear evidence of conformational shifts, even within complex mixtures. Following collisional heating, protein ions can unfold, and the amount of acceleration voltage needed to produce a fixed level of protein ion unfolding can be used to measure the stability shifts upon ligand binding. Finally, we can track gas-phase protein unfolding in a more comprehensive way and create collision induced unfolding (CIU) 'fingerprints' of ligand bound states and rapidly compare these with libraries of CIU data collected for known binders. After determining what type of IM-MS screening mode is most appropriate for a given application, high-throughput screening of chemical libraries in our laboratory can be initiated through robotic sampling and software packages developed in-house to rapidly interpret results. We are currently pursuing such library screening efforts in the areas of Alzheimer's disease and cancer treatment discovery efforts.