A cryo-capable electron microscope for the Astbury Biostructure Laboratory

Structural biology is a powerful tool in biological discovery. It can reveal the molecular details of how proteins and other molecules interact, and so help us understand fundamental biological processes that have enormous implications in areas as diverse as human/animal health and wellbeing, food security and biotechnology. One of the cornerstones of modern structural biology is a technique called electron microscopy, where powerful microscopes are used to take highly magnified images of biological material such as proteins, from whcih we can work out the three-dimensional structure of the protein complexes. CryoEM (imaging frozen samples) can now address structural problems of unprecedented scale and complexity, and the results are transforming our understanding of biology.

The Astbury Biostructure Laboratory at the University of Leeds is an internationally-recognised cryoEM facility that supports large numbers of scientists from Universities and Industry, and from the UK and beyond. We currently operate two ultra-high-end electron microscopes that have just been updated to the latest technology. However when new samples arrive in our facility, and new projects are started, these high-end microscopes sit at the end of a pipeline that starts with lower-end electron microscopes. For every such sample, routine electron microscopes are used to quickly image a sample and assess its quality and suitability for high-resolution imaging. Routine electron microscopes are also absolutely essential to the process of optimising how samples are prepared for high end-imaging. Routine imaging is therefore essential to every project that ultimately leads to a high resolution structures.

However, the microscopes available to us for routine imaging at the Astbury Biostructure Laboratory (and the detectors on those microscopes) are rapidly becoming obsolete, becoming difficult and expensive to maintain, and uneconomic or impossible to upgrade. We therefore wish to secure funding from this grant application to buy a new electron microscope, with a modern detector, and modern software allowing remote operation, for routine imaging and sample optimisation. This will allow us to retire two ageing microscopes, reducing our space and costs, and shrinking the carbon footprint of our facility.

The new microscope will support all of the exciting structural projects currently underway, and this application describes a subset of these in four major themes: (1) proteins that sit in the protect membranes around cells, (2) the structure and function of viruses; (3) large protein assemblies; and (4) proteins that aggregate. In addition, the Astbury Biostructure Laboratory is now a major centre for cryoEM training, and the new microscope will directly support this activity, helping us to drive an increase in the skills needed to use cryoEM for biological discovery.

Structural biology is a uniquely powerful tool in modern biological research, and cryo-electron microscopy and cryo-electron tomography are now two of its cornerstones. CryoEM/ET can address structural problems of unprecedented scale and complexity, and the results are transforming our understanding of biology. The Astbury Biostructure Laboratory at the University of Leeds is an internationally-recognised cryoEM facility that supports large numbers of scientists from Universities and Industry, and from the UK and beyond. We currently operate two Titan Krios EMs, recently upgraded to F4 and F4/selectris detectors, and to be further upgraded to Falcon4i in Q2/2022. However, the first step in almost all structure projects in EM is negative stain imaging where routine electron microscopes are used to quickly image a sample and assess its quality and suitability for high-resolution imaging. Such EMs are also absolutely essential to the process of optimising how samples are prepared for high end-imaging. Access to a routine EM for imaging is therefore essential to every project that ultimately leads to a high resolution structure.

However, the microscopes available to us for this kind of imaging, and their detectors are rapidly becoming obsolete, becoming difficult and expensive to maintain, and uneconomic or impossible to upgrade. We therefore wish to secure funds to buy a new EM - suggested to be a Thermo-Fisher Talos L120C G2 TEM equipped with a 'cryo-box'
anti-contamination system, and with a Ceta fast CMOS detector, and modern software allowing remote operation. The improved reliability and ease of operation will allow us to retire two ageing microscopes, reducing our space and costs, and shrinking the carbon footprint of our facility, whilst enhancing this essential imaging capability and allowing us to train new users (both internal and externally).