Laboratory of Molecular Biophysics Laboratory Journal 2007 X-Ray Facilities

X-ray Facilities Report. LMB 2006-2007.

Ed Lowe and Elspeth Garman

During 2007-2008, the T3 X-ray facility, consisting of a 2.7 kW Bruker MicroStar X-ray generator with Montel optics on both sides, a Mar345 Imaging plate detector on the right hand side and a Bruker SMART 6000 CCD detector with 4-circle kappa goniometer on the left hand side (Figure 1), has continued to run well this year. Filament lifetime has continued to be extremely good, with only two filament changes being necessary this year.

Figure 1. Bruker Microstar generator with kappa goniometer.

The Cobra liquid nitrogen-less cryostat prototype installed in 2006 has continued to run well and has been in almost constant use. We have continued to use it in conjunction with a Parker NitroFlow nitrogen generator.

We have experienced one major technical problem, with a fault in the power supply of the CCD detector occurring in November 06. Detection and repair of this fault was carried out by Bruker engineers and the detector was in service again by January 07.

The Microstar system continues to be heavily used for the determination of new structures. Prof. Jane Endicott's group has solved the structure of the VWA domain of Pus1, a component of the proteasome, using S-SAD phasing data collected on the Microstar in conjunction with native data collected on beamline ID14.EH2, ESRF (Figure 2). Prof. Martin Noble's group has continued investigations on the CH domain of actopaxin, determining the structures of the protein in complex with three different peptide ligands by molecular replacement. Members of the CRL, including Dr. Mike McDonough and Dr. Ian Clifton, have continued to make use of the facility.

Figure 2. Electron density maps showing the structure of the Pus1 VWA domain. In green is the experimentally phased Fo map contoured at 1(. In yellow is an anomalous Fourier map contoured at 5( showing the position of sulphur atoms in the structure.

The T5 RU200H generator with a Mar345 imaging plate detector and Osmic optics again ran very smoothly this year. A new vacuum pump was fitted to the Osmic optics and the anode annual rebuild was carried out by us in October. Experiments carried out using it include investigations of room temperature radiation damage by the group of Dr. Elspeth Garman and have just been published (Structure 15 (2007) 1531-1541).