New Beamline at Diamond Light Source is used to Study Bird Flu

Date Posted: Thursday, August 14, 2008

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The eleventh experimental station to come online at the UK’s synchrotron facility has received its first users, a research group from the MRC-National Institute for Medical Research (NIMR), based in London, focusing on the structure and function of protein complexes that are involved in medically important disease processes.

The new Microfocus Macromolecular Crystallography (MX) beamline (I24) will be a major asset to the UK structural biology programme, joining a suite of three MX beamlines already in operation at Diamond. It will enable measurements on small crystals that are not possible on the beamlines currently available, helping scientists to investigate the relationship between the structure of large macromolecules and their function within living organisms, a key aim of modern biology.

MX is the most powerful method for determining the atomic 3D structures of large biological molecules. It is a vital tool for linking structure with function, for rational drug design, for investigating protein folding and for relating other structural information, such as evolutionary relationships, from biological molecules.

Macromolecules tend to form small, imperfect and weakly diffracting crystals. The high brightness of Diamond’s X-rays makes the collections of precise measurements possible.

I24 is part of the Phase II construction at Diamond which is due to be complete in 2012. The further 11 Phase II beamlines that are scheduled to be added over the next four years will bring the total of operational beamlines at Diamond to 22, covering a wide range of science; from biology and medicine, to the physical and chemical sciences, through to the environmental and earth sciences.

Dr Steve Gamblin and his team from the NIMR used Diamond as part of their studies into how bird flu could spread to humans. The influenza virus has two major surface glyco-proteins hemagglutitinin (H) which enables the virus attach to human cells and the enzyme neuramidase (N) which allows newly made virus to escape from its host cell to spread infection. There are 16 subtypes of H and nine of N, occurring in all combinations, with the current strain of bird flu being H5N1.

The NIMR team used Diamond’s extremely intense X-rays to take a closer look at a crystal of bird flu H5 in which a mutation has arisen which enables the bird flu’s hemagglutitinin to bind to human cells. This is one of the key changes that are thought to be necessary for the disease to spread from birds to humans.

Although bird flu is currently relatively difficult for humans to catch, studies on the emergence of such mutations are essential for surveillance and pandemic preparedness.

The NIMR team’s time at Diamond was fruitful. Figure.1 shows one of the diffraction patterns achieved from a crystal of a mutant hemagglutinin from H5N1, helping to inform the group of the structure of this protein and therefore how it could bind to a human cell.

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