The Microfocus MX beamline is the first dedicated microfocus tuneable beamline for MX experiments in Europe.

A key aim of modern biology is to relate the detailed atomic arrangement of large macromolecules to their function within living organisms. The availability of intense, tuneable and highly collimated radiation from synchrotron sources, together with cryogenic sample handling and greatly improved data collection and analysis has revolutionised the field. More than 70% of all structure determinations of macromolecules involved the use of synchrotron radiation. The UK has been strongly represented in this activity and UK workers have been credited with many of the significant advances.

Increasingly, a critical restraint on the application of x-ray diffraction has been the difficulty in obtaining crystals of sufficient size (50-100 microns) and order to generate the high quality diffraction patterns required for the detailed analysis. This is notably true for membrane proteins and multi-protein complexes, which play a central role in cellular operation. A consequence of the drive to increase the rate of crystal automation of protein expression, screening and crystallisation is the growing dependence on small amounts of material for the structural determination. A solution to this problem is to reduce the beamsize and preferentially illuminate smaller crystals or more perfect regions.

The microfocus beamline will have a beamsize at the sample of 5-30 microns, and will be a major asset for the UK structural biology programme. It will enable measurements on small crystals that are not possible on conventional beamlines due to their small size or mosaicity, and will improve the screening of crystals for optimisation of crystallisation conditions.

Membrane Protein Laboratory

Beamline I24 benefits from its close proximity to the Membrane Protein Laboratory (MPL). The MPL provides equipment, training and expertise in the area of membrane protein crystallisation and crystallography to the membrane protein X-ray crystallography community. The MPL has a formal collaboration with I24 to develop new techniques for crystallisation and structural determination of membrane proteins, including prototype systems for high throughput methods, improving handling of small and delicate crystals, and methods for collecting and merging data from a large number of small crystals. This will lead to substantial improvements in the rate at which structures of membrane proteins are solved.