A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

作者：Murray Thomas D; Lyubimov Artem Y; Ogata Craig M; Huy Vo; Uervirojnangkoorn Monarin; Brunger Axel T^*; Berger James M

来源：Acta Crystallographica Section D-Structural Biology, 2015, 71(10): 1987-1997.

DOI：10.1107/S1399004715015011

• microcrystals
• silicon nitride
• serial data collection
• XFEL
• microfocus beamline
• X-ray crystallography
• microfluidics

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 mu l) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called 'fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10-15 mm) loaded into the chips yielded a complete, high-resolution (<1.6 angstrom) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.

• 出版日期2015-10