BIOCRYSTALLOGRAPHY AT THE HIGH BRILLIANCE BEAMLINE (ID2) OF THE ESRF. E. P. Mitchell, A. Aberg, J. Shaw, S. Wakatsuki, D. Spruce, L. Claustre, P. Bosecke, O. Diat, B. R. Rasmussen, ESRF, BP 220, F-38043, Grenoble Cedex, France, EMBL, 38042 Grenoble Cedex, France

The high brilliance beamline at the ESRF is one of the most intense sources of low divergence X-rays for protein crystallography. The beamline has been designed with studies on large cell proteins and small crystals in mind.

Recent and ongoing improvements to the protein crystallography end station of the ESRF high brilliance beamline now make routine data collection from crystals with very large unit cells (for example viruses and ribosomes) and very high resolution data possible. Notably data has been successfully collected from crystals of Blue Tongue Virus (largest unit cell dimension 1550Å; Stuart et al, Oxford, UK).

Until recently a complete 30cm MAR Research system was used, now a five circle Huber diffractometer, retaining only the MAR detector itself, has been installed, with cryogenic cooling possible and a maximum crystal to detector distance of 1 metre. The fifth circle (d2) of the goniometer allows an angular rotation of +/-20deg. on the long detector arm. The fourth shorter circle (d1) allows mounting of a scintillation counter for ease of alignment. It is envisaged that the d1 arm could also be used to mount a small fast-scan CCD camera for the purpose of screening crystals (for example heavy metal derivatives) speedily.

New software for a rational data collection strategy using the Huber goniometer is being developed. The aim is to use the flexible Huber goniometer to its full capacity and maximise data collection efficiency. The software will use a graphical user interface (TclTk) to allow smooth use of the beamline.