An inexpensive automatically operated device for the flash annealing of crystals of macromolecules

In order to prolong the life-time of crystals in an X-ray beam, modern macromolecular crystallography is mainly performed using cryogenically cooled samples. However, in many cases flash cooling can degrade crystal quality if cryoprotection conditions are not ideal. Annealing or tempering of samples adversely affected by cryocooling can often, at least partially, restore diffraction quality and is now considered a standard technique in macromolecular crystallography. A small, inexpensive, automatically operated annealing device that is installed on all ESRF macromolecular crystallography beamlines is presented here. The device allows, via the beamline control graphical user interface mxCuBE, the flash annealing of samples either from the beamline control cabin or by users accessing the beamline remotely.