Crystal cooling for protein crystallography with synchrotron radiation

Abstract

A new crystal cooling device for protein data collection with a rotation camera at temperatures between 323 and 100 K is described. It includes a flow cell for solvent exchange at low temperatures. The crystal is mounted in a double chamber with thin Mylar walls. The temperature is controlled to better than 0.5 K by N2 or He gas flowing through the inner chamber. Since cooling is isotropic, temperature gradients near the sample are avoided. Dry gas circulating through the outer chamber prevents the windows from icing. The system has been routinely used for synchrotron radiation data collection at the instrument X ll at DORIS. The scope of applications in low-temperature protein crystallography with synchrotron radiation is discussed.