Spitrobot-2 advances time-resolved cryo-trapping crystallography to under 25 ms

We previously introduced the spitrobot, a protein crystal plunging system that enables reaction quenching via cryo-trapping with a time resolution in the millisecond range. Here we present the next generation, spitrobot-2, as an integrated benchtop device. User-friendliness has been improved by semi-automatic sample exchange. Moreover, a fully automated shutter shields the liquid nitrogen from the humidified environment, improving sample integrity. Most importantly, the cryo-trapping delay time has been reduced to 23 ms, making spitrobot-2 twice as fast as the previous generation. This further expands the number of target systems that can be addressed by cryo-trapping time-resolved crystallography. Using 12 crystal structures of three independent model systems, we demonstrate successful cryo-trapping via observation of conformational changes and ligand binding within 25 ms. These improvements increase the convenient access to cryo-trapping, time-resolved X-ray crystallography empowering the MX community with efficient tools to advance research in structural biology.