Search

Serial crystallography (SX) provides room‐temperature crystal structures with minimal radiation damage and facilitates the comprehension of molecular dynamics through time‐resolved studies. In SX experiments, it is important to deliver a large number of crystal samples to the X‐ray interaction point in a serial and stable manner. The advantage of crystal delivery in a viscous medium via a capillary is the ability to deliver all of the crystal samples to the X‐ray interaction point at a low flow rate; however, the capillary often breaks during handling and high X‐ray absorption can occur at low energy states. This study aimed to develop a stable system for sample delivery in a viscous medium via a polyimide‐based single‐channel microfluidic (PSM) chip for SX. Since this microfluidic chip comprises a polyimide film, it has high tensile strength and higher X‐ray transmittance than a quartz capillary. The PSM chip was connected to a syringe containing the microcrystals embedded in viscous medium. The channel of the PSM chip was aligned to the X‐ray path, and the viscous medium containing lysozyme crystals was stably delivered using a syringe pump at a flow rate of 100 nl min−1. Room‐temperature lysozyme crystal structures were successfully determined at 1.85 Å resolution. This method would greatly facilitate sample delivery for SX experiments using synchrotron X‐rays. [ABSTRACT FROM AUTHOR]

Serial crystallography (SX) is an innovative technology in structural biology that enables the visualization of the molecular dynamics of macromolecules at room temperature. SX experiments always require a considerable amount of effort to deliver a crystal sample to the X‐ray interaction point continuously and reliably. Here, a sample‐delivery method using a capillary and a delivery medium is introduced. The crystals embedded in the delivery medium can pass through the capillary tube, which is aligned with the X‐ray beam, at very low flow rates without requiring elaborate delivery techniques, drastically reducing sample consumption. In serial millisecond crystallography using a viscous medium via a capillary, crystals of lysozyme embedded in agarose, which produce an unstable injection stream at atmospheric pressure, and crystals of glucose isomerase embedded in gelatin, which is known to be problematic for open‐extruder operation, were stably delivered at a flow rate of 100 nl min−1. The room‐temperature crystal structures of lysozyme and glucose isomerase were successfully determined at 1.85 and 1.70 Å resolutions, respectively. This simple but highly efficient sample‐delivery method can allow researchers to deliver crystals precisely to an X‐ray beam in SX experiments. [ABSTRACT FROM AUTHOR]