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

Abstract

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.

ID30A-3 (MASSIF-3) – a beamline for macromolecular crystallography at the ESRF with a small intense beam

“…2(a)] comprises a MD2 micro-diffractometer (Arinax, Voreppe, France; permanent loan from EMBL Grenoble Outstation), an Eiger X 4M detector (Dectris, Baden-Daettwil, Switzerland; Casanas et al, 2016; Fö rster et al, 2019) mounted on a fast translation table, and a FlexHCD robotic sample changer (McCarthy et al, 2018). Samples on the rotation axis of the MD2 are kept at cryogenic temperature using a 700 series cryo-stream (Oxford Cryostreams, Oxford, UK) equipped with an annealing system (Giraud et al, 2009). The entire experimental setup [ Fig.…”

Approaches to automated protein crystal harvesting

“…Firstly, the vacuum line connected to the micropipette opens, removing the mother liquor from the crystal. Secondly, a high-speed air-driven shutter is actuated on the cryostream (Giraud et al, 2009). The precision and high speed of these events ensures that the crystal is efficiently flash-cooled.…”

MxCuBE: a synchrotron beamline control environment customized for macromolecular crystallography experiments

“…Other general features available via Hutch tab bricks include: changing the size and intensity of the X-ray beam incident on the sample (the 'slit' and 'transmission' bricks), automatic annealing of the sample currently mounted (Giraud et al, 2009), opening and closing of beamline shutters (for beam visualization on scintillator crystals) and in/out positioning of the beamstop (fine alignment of the beamstop is available in 'Expert' mode). The motor positions of the add-on mini-kappa goniometer head (McCarthy et al, 2009) are also monitored and controlled using the Hutch tab.…”