Division of Biotechnology, Korea University, Seoul, Republic of Korea.
Institute of Life Science and Natural Resources, Korea University, Seoul, Republic of Korea.
Sci Rep. 2020 Jan 9;10(1):107. doi: 10.1038/s41598-019-56135-1.
Serial crystallography allows crystal structures to be determined at room temperature through the steady delivery of crystals to the X-ray interaction point. Viscous delivery media are advantageous because they afford efficient sample delivery from an injector or syringe at a low flow rate. Hydrophobic delivery media, such as lipidic cubic phase (LCP) or grease, provide a stable injection stream and are widely used. The development of new hydrophobic delivery materials can expand opportunities for future SX studies with various samples. Here, I introduce fat-based shortening as a delivery medium for SX experiments. This material is commercially available at low cost and is straightforward to handle because its phase (i.e., solid or liquid) can be controlled by temperature. Shortening was extruded from a syringe needle in a stable injection stream even below 200 nl/min. X-ray exposed shortening produced several background scattering rings, which have similar or lower intensities than those of LCP and contribute negligibly to data processing. Serial millisecond crystallography was performed using two shortening delivery media, and the room temperature crystal structures of lysozyme and glucose isomerase were successfully determined at resolutions of 1.5-2.0 Å. Therefore, shortening can be used as a sample delivery medium in SX experiments.
连续结晶学可以通过将晶体稳定地输送到 X 射线相互作用点来实现室温下的晶体结构测定。粘性输送介质具有优势，因为它们可以在低流速下从注射器或注射器中高效输送样品。疏水性输送介质，如类脂立方相（LCP）或油脂，提供稳定的注入流，因此被广泛使用。新型疏水性输送材料的开发可以为未来各种样品的 SX 研究提供更多机会。在这里，我介绍脂肪基起酥油作为 SX 实验的输送介质。这种材料价格低廉，易于处理，因为其相（即固态或液态）可以通过温度来控制。起酥油甚至在低于 200nl/min 的流速下从注射器针头中以稳定的注入流挤出。用两种起酥油输送介质进行了毫秒级连续结晶学实验，成功地在室温下测定了溶菌酶和葡萄糖异构酶的晶体结构，分辨率达到 1.5-2.0Å。因此，起酥油可以用作 SX 实验中的样品输送介质。
