Using a Free Electron Laser to Improve Atomic Level Biological Imaging

High resolution science requires high energy beams. The downside is that high energy beams are also extremely destructive. Structural biologists working to visualize the complex atomic world underlying living things face a fundamental problem because the beams of X-rays or electrons they use destroy samples before they can be clearly seen. Research from a New Zealand / German collaboration published this week in the journal Proceedings of the National Academy of Sciences of the United States of America aims to solve this problem using a giant new X-ray laser to record structural information from samples a few femtoseconds before they explode. Despite using radiation doses hundreds of times greater than previously used in structural biology and over thirty million times the fatal dose for humans, the experiment was a success revealing the atomic structure of a nano-crystalline virus without damage, validating the idea and pointing the way forward to future X-ray imaging of non-crystalline biological samples.

Atomic model of the crystalline occlusion bodies, derived from the X-ray diffraction images recorded at the LCLS. The individual proteins (right) stick together to form the building blocks (left, seen from the side; centre, seen from above) of the crystalline occlusion bodies. Credit: Dominik Oberthür, CFEL/DESY

Peter Metcalf, from the School of Biological Sciences at the University of Auckland, has been working with insect virologist Johannes Jehle from the Julius Kühn Institute in Damstadt on granulovirus since 2008 and started the collaboration with Henry Chapman at the Centre for Free Electron Science in Hamburg in 2011. He commented ‘It has been a huge privilege to work with Henry and the team of over 40 people at the Centre for Free Electron Laser Science in Hamburg and the Linear Coherent Light Source at Stanford using a billion dollar machine to elucidate the atomic structure of an esoteric nano-crystalline codling moth virus, but more importantly to make progress overcoming the fundamental damage problem in structural biology.’

The research was supported by Marsden contract UOA1221 awarded in 2012: “Towards atomic resolution biological imaging using free electron X-ray laser radiation – the granulovirus connection”.

More news can be found about the publication on the DESY website.