Developing mass spectrometry to understand molecular mechanisms of antibacterial and antiviral drugs

The search for new antibiotcs has become more acute as the COVID-19 pandemic has brought a surge in antimicrobial usage that is expected to drive up resistance. Here, we seek to uncover the targets and mechanisms of action of antibiotics and antivirals - aspects that remain, for many drugs, poorly understood or completely unknown. To investigate the mechanisms of action of antibiotics - both new and re-engineered - we have assembled a series of mass spectrometry-based assays, involving in vitro synthesis of bacterial cell-wall components and a clear indication of bacterial lipid flippase activity. Where targets are unknown, we will eject complexes directly from bacterial membranes, monitoring antibiotic responses over time and thereby identifying targets in situ. We also aim to identify new antibiotic targets, by establishing a mechanistic understanding of the membrane-embedded enzymes and multiprotein complexes responsible for remodelling and synthesising components of bacterial cell envelopes. Though extremely difficult to study via standard biophysical approaches, these enzymes and complexes are essential for bacterial survival; a better understanding of them will be invaluable for antibiotic targeting. For our COVID-19 research theme, we will continue our studies with existing antivirals, covering additional drugs that have shown activity in in vitro assays of virus proliferation. Probing interactions among the SARS CoV-2 main proteins, RNA and accessory factors - and, applying our expertise in membrane protein-lipid interactions, we will explore emerging COVID-19 targets, such as the two-pore cation channel in the lysosomal degradation pathway. Bringing antibacterial and antiviral studies together allows synergistic discoveries and consideration of repurposed drugs active in both scenarios, and enables us to contribute to tackling the biggest global health challenges of our time.