Microcrystal sample delivery for serial crystallography in a high viscosity medium

Uwe Weierstall, Department of Physics

Arizona State University, Tempe 85287, USA

Serial crystallography at XFEL’s has shown great promise in recent years for solving crystal structures from proteins which grow only micron sized crystals. G-protein coupled receptors are an important group of membrane proteins which are often crystallized in Lipidic Cubic Phase (LCP). This material has very high viscosity, and a device has been developed, which allows the generation of a microscopic stream of LCP with adjustable speed for sample delivery to the X-ray beam [1]. Some important GPCR structures could be solved with this device at the LCLS [2]. In addition, new media with similar viscosity to LCP have been developed which enable delivery of soluble or membrane proteins into the X-ray beam with low sample consumption [3].  The high viscosity injection method has also been shown to facilitate serial diffraction experiments with microcrystals at synchrotron microfocus beamlines. This talk will highlight these developments and discuss the possibilities.

1.         Weierstall, U., James, D., Wang, C., White, T. A., Wang, D., Liu, W., et al. (2014). Lipidic cubic phase injector facilitates membrane protein serial femtosecond crystallography. Nature Communications, 5. http://doi.org/10.1038/ncomms4309

2.         Kang, Y., Zhou, X. E., Gao, X., He, Y., Liu, W., Ishchenko, A., et al. (2015). Crystal structure of rhodopsin bound to arrestin by femtosecond X-ray laser. Nature, 523(7562), 561–567. http://doi.org/10.1038/nature14656

3          Conrad, C. E., Basu, S., James, D., Wang, D., Schaffer, A., Zatsepin, N. A., et al. (2015). A novel inert crystal delivery medium for serial femtosecond crystallography. IUCrJ, 2(4), 421–430.