Diamond Concise Annual Review 2019/20

D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 1 9 / 2 0 D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 1 9 / 2 0 14 15 T his Group brings together dedicated facilities for X-ray, light and electron microscopy at Diamond Light Source. The full field cryo- transmission X-ray microscope (cryo-TXM) is dedicated to biological X-ray imaging on beamline B24 and the beamline has also established a cryo super resolution fluorescence microscopy facility as a joint venture with the University of Oxford. The Group also includes the electron Bioimaging Centre (eBIC) which is the national centre for cryo-electron microscopy (cryo-EM) in the UK and provides a range of capabilities and supporting facilities for cryo-EM. The Group plans to further expand its bio-imaging capabilities and increase its impact in the field of 3D imaging during 2020. Studies undertaken this year include detailed analysis of the structures of human and avian flu viruses which could lead to the development of new antiviral drugs against flu, and increased understanding of the mechanisms underlying a rare genetic disorder. Studying newways to tackle flu Influenza (the flu) is caused by influenza A viruses and results in annual pandemics. To stay one step ahead of the flu outbreaks, scientists at Diamond are trying to decipher the structure and mechanisms of influenza A viruses. When the virus infects host cells, it makes many copies of its RNA genome to produce new virus particles. The enzyme responsible for this genome replication is called RNA-dependent RNA polymerase, or FluPolA. A team of researchers from the University of Oxford used cryo-EM imaging at eBIC to analyse the influenza virus polymerase. They also used the Macromolecular Crystallography beamlines I03, I04, and I24 to analyse crystals of the polymerase. Using X-ray crystallography, they were able to obtain the first, high-resolution structures of FluPolA of human and avian influenza viruses, revealing crucial details of how the structure of FluPolA is vital in initiating RNA synthesis. Using cryo-EM allowed them to study the protein binding to an RNA template. These results suggest potential targets to inhibit virus reproduction. In the future, this could lead to the development of antiviral drugs against the flu. Fan H et al . doi:10.1038/s41586-019-1530-7 Increasing understanding of Fanconi Anaemia Fanconi Anaemia (FA) is a rare and serious genetic illness that causes abnormal development, bone marrow failure and a lifetime risk of developing cancer. FA results in impaired response to DNA damage – it deactivates 13 genes that code for proteins that function collectively to repair damaged DNA. These genes and proteins are known as the FA repair pathway which is normally responsible for the repair of damaged crosslinks within and between strands of DNA. At the centre of this pathway is the multi-protein FA core complex which is able to identify and signal the site of DNA crosslinks. When the FA pathway is defective, it results in serious human disease. Although the FA core complex had been characterised in cells, it had not been fully reconstituted in the laboratory. Researchers at Diamond isolated an FA core complex and determined its structure using Cryogenic Electron Microscopy (cryo-EM) at eBIC to image the complex at high resolution. They created 3D reconstructions from the images and used them to build models of the FA core complex assembly and function. This long-term investigation took ten years to progress from project conception to the final determination of FA core complex structure. Researchers can now use these models to conduct further studies on the function of the FA core complex functions and begin to define this DNA repair pathway in molecular terms. This will help to explain why specific patient mutations inactivate this critical pathway. In the future this imaging work at eBIC may allow scientists and clinicians to improve management of FA by predicting whether certain changes might cause disease. Shakeel S et al . doi: 10.1038/s41586-019-1703-4 Biological Cryo-Imaging Group