Structural Studies on Viruses, Viral Proteins and Cell Interactions

Viruses outnumber all other organisms on the globe. These nano-parasites reproduce inside our cells, so they are often very difficult to combat. Some 33 million people are infected with HIV and many other human viruses also have a terrible impact on human health. Viruses include hundreds of major human pathogens and are responsible for millions of deaths every year. Nevertheless many of these diseases can in principle be prevented or treated - smallpox was declared eradicated in 1979 and this year or next the United Nations Food and Agriculture Organisation is likely to declare the global eradication of rinderpest, a devastating scourge of cloven footed animals. This is encouraging and suggests that the closely related measles virus might also succumb to a concerted vaccination campaign. Despite these successes there are still many viruses which we are unable to control by vaccination. Drugs play a complementary role, for treating people already infected. The pharmaceutical and biotechnology industries pump considerable money into anti-viral research and development and the range of drugs now available to combat HIV shows that this strategy can be very effective. However the unexpected emergence of SARS and swine ?flu shows that we cannot predict the next major virus outbreak so it is sensible to support basic research - to be better prepared to respond to the unexpected. This proposal for such underpinning research comes from David Stuart, a Medical Research Council Professor based at the Nuffield Department of Medicine at Oxford University. The work will deliver new information about viruses, in the form of portraits in atomic detail, made freely available in public databases for use by academic or commercial experts in drug and vaccine design. We think that there is a real chance that this knowledge will eventually allow safer and more robust vaccines to be designed. This work is only possible using the very bright X-ray beams provided by the UK synchrotron, Diamond, allowing us to see these particles that are invisible through a normal microscope. The first aim of the work is to improve the experimental technology to facilitate data collection from pathogens and then to investigate several viruses which represent major burdens on global health, including the three major hepatitis viruses A, B and C. For some of the simpler viruses we will see if structural knowledge can be used to guide the development of improved vaccines.

This application is for the renewal of a programme focused on virus structure analysis which includes technical development, and spans from basic research into fundamental questions of function and taxonomy, through to work to underpin the development of improved vaccines and anti-viral drugs.

Technical developments comprise the first aim: novel methods for X-ray structure determination in situ (i.e. avoiding any handling of crystals), the investigation of novel crystal freezing methods and exploration of the limits of X-ray analysis for small arrays of virus particles in cells using diffraction and imaging.

These methods underpin three biomedical themes: (i) to tackle some major outstanding questions concerning picornaviruses, (ii) to understand a major vaccine particle, that of hepatitis B, and to determine novel structures to map the landscape of the viral universe, and (iii) to work towards a more comprehensive view of virus fusion.

Theme (i) includes the investigation of the atomic structures of hepatitis A, EV71 and a newly assigned nonclassical picornavirus (Ljungan or a parechovirus); investigation of assembly /disassembly pathways including analysis of a representative picornavirus heavy particle; and the design and structure determination for recombinant mutant picornavirus capsids with increased stability, to establish rules for improved vaccines.

For theme (ii) we will work towards the high resolution X-ray structure of the hepatitis B surface antigen particle and initiate crystallographic analyses of novel viruses from a virus ecology pipeline.

Theme (iii) builds on existing work on viral fusion proteins, with a particular focus on hepatitis C E1 and E2 proteins and E2 of the bovine viral diarrhoea pestivirus. We will also initiate work on a markedly different and complex fusion system from vaccinia virus.

The programme includes the analysis of viruses responsible for major global health burdens (including hepatitis A, B and C viruses) and will contribute to the body of structural information freely available in the public domain, which can be used both by academics and commercial organisations for structure-guided drug discovery. In addition we will work in a more translational fashion on vaccine design. As appropriate we will form collaborations to maximise exploitation of the results, a strategy exemplified by our current work on foot-and-mouth disease virus vaccine (with Intervet/Schering-Plough Animal Health).