Recent developments in microdiffraction on protein crystals

J. Synchrotron Rad. (2004). 11, 4-6 [doi:10.1107/S090904950302541X]

Cryocooled crystal of bovine rhodopsin visualized on the microgoniometer. (Courtesy of G. Schertler, Cambridge)

A dedicated microgoniometer for synchrotron radiation protein crystallography has been developed at EMBL-Grenoble in collaboration with ESRF. Beam sizes down to about 5 μm and a compact pinhole collimating system allow reducing background scattering from the sample environment, which is important for small and weakly scattering crystals such as membrane proteins. A microscope, coaxial to the X-ray beam, facilitates sample alignment. Needle-like protein crystals of about 10 μm diameter of trigonal bovine rhodopsin belong to the currently smallest protein crystals studied.