Biological Physics Seminars 2023/2024

The development of glycan-protein cross-linking mass spectrometry to investigate host-pathogen interactions

Dr Sean Burnap; Struwe Group, Dept. of Chemistry & Kavli, University of Oxford

Abstract:

Viruses rely on their membrane-bound surface proteins to enable host cell attachment and subsequent infection. Enveloped viral surface glycoproteins, often termed “spikes”, are some of the most heavily glycosylated proteins in nature, and are at the forefront of vaccine development. Importantly, glycans are able to protect immunological epitopes under a dense “glycan shield”, hindering immune cell recognition, as well as playing a central role in interactions with host proteins. The investigation of glycan function and structure is however impeded by the huge degree of structural diversity, arising from their non-template biosynthesis, thus rendering traditional biophysical techniques unsuitable for their study. Harnessing metabolic engineering approaches, we are developing glycan-protein crosslinking mass spectrometry to elucidate glycan and glycoprotein functionality in host-pathogen interactions.

Structural analysis of the influenza genome by high-throughput single-virion DNA-PAINT

Dr Christof Hepp; Kapanidis Group, Biophysics & Kavli, University of Oxford

Abstract:

Influenza A, a negative-sense RNA virus, has a genome that consists of eight single-stranded RNA segments. During influenza co-infections, re-assortant virus strains containing gene segments from either strain can occur, occasionally leading to pandemic outbreaks with severe, worldwide consequences for human health. To better understand the formation of these potentially pandemic re-assortants, we analysed the selective packaging of all eight RNA segments into virions. To this end, we designed a novel multiplexed DNA-PAINT approach capable of a) detecting the presence or absence of all eight gene segments inside of more than 10,000 individual virus particles in one experiment in just 4 hours and b) spatially resolving the individual segments inside complete virus particles with a resolution of better than 10 nm. With its high throughput and the capability of unambiguously identifying specific gene segments, this experiment provides novel structural information complementing electron microscopy studies. Our results suggest a flexible network of inter-segment interactions that form a robust genome assembly for influenza A. In the long term, we will develop our experimental approach for the structural and functional study of viral nucleoprotein complexes in infected cells to elucidate key elements of the viral life cycle like transcription, replication and sub-cellular transport.