Fixed target combined with spectral mapping: approaching 100% hit rates for serial crystallography

Abstract

The advent of ultrafast highly brilliant coherent X-ray free-electron laser sources has driven the development of novel structure-determination approaches for proteins, and promises visualization of protein dynamics on sub-picosecond timescales with full atomic resolution. Significant efforts are being applied to the development of sample-delivery systems that allow these unique sources to be most efficiently exploited for high-throughput serial femtosecond crystallography. Here, the next iteration of a fixed-target crystallography chip designed for rapid and reliable delivery of up to 11 259 protein crystals with high spatial precision is presented. An experimental scheme for predetermining the positions of crystals in the chip by means of in situ spectroscopy using a fiducial system for rapid, precise alignment and registration of the crystal positions is presented. This delivers unprecedented performance in serial crystallography experiments at room temperature under atmospheric pressure, giving a raw hit rate approaching 100% with an effective indexing rate of approximately 50%, increasing the efficiency of beam usage and allowing the method to be applied to systems where the number of crystals is limited.

Drop-on-demand sample delivery for studying biocatalysts in action at X-ray free-electron lasers

“…Ejection from an ADE has a high upper bound for the crystal size, while keeping sample consumption at low levels, orders of magnitude lower than Rayleigh jets of the same pathlength. Fixed-target systems have also been successfully used at XFEL facilities 11–14 , but such systems have not yet been demonstrated for multi-modal data collection.…”

Towards an Optimal Sample Delivery Method for Serial Crystallography at XFEL

“…Many fixed-target chip designs employ crystalline silicon [130][131][132][133][134] or silicon nitride [126,[135][136][137][138]. These materials are chosen for their low scattering background, high transmission to X-ray and great precision in microfabrication using photolithography technique.…”

Microfluidics: From crystallization to serial time-resolved crystallography

“…The current data acquisition rate at the LCLS is typically 120 Hz, resulting in estimated crystal hit rates on the order of 0.01%-0.1%. 147,160,161 Thus, sample utilization at synchrotron sources would be prohibitive. However, for the higher MHz-level data acquisition rates anticipated at the European XFEL and the LCLS II, more optimal sample utilization should be achievable.…”