Cryo bio-crystallography
Cryo bio-crystallography is the application of crystallography to biological macromolecules at cryogenic temperatures.
Basic principles
Cryo crystallography enables X-ray data collection at cryogenic temperatures, typically 100 K.
- Crystals are transferred from the solution they have grown in (called mother liquor) to a solution with a cryo-protectant to prevent ice formation.
- Crystals are mounted in a glass fiber (as opposed to a capillary.)
- Crystals are cooled by dipping directly into liquid nitrogen and then placed in a cryo cold stream.
- Cryo cooled macromolecular crystals show reduced radiation damage by more than 70 times that at room temperature.
Advantages
- Significant improvement of resolution in data collection
- Reduced or eliminated radiation damage in crystals
Usefulness and applications
Crystallography of large biological macromolecules can be achieved while maintaining their solution state. The best known example is the ribosome.[1] Today, liquid nitrogen cryo cooling is used for protein crystallography at every synchrotron around the world. Radiation damaged is reduced by more than 70 fold at cryo temperatures. A recent review paper explains the development of reduced radiation damage in macromolecular crystals at Synchrotrons and describes how more than 90% of all structures deposited in the Protein Data Bank used cryo cooling in their determination.
2020 Haas, DJ. The early history of cryo-cooling for macromolecular crystallography (2020) IUCrJ (2020). 7, 148–157. https://journals.iucr.org/m/issues/2020/02/00/be5283/be5283.pdf 1970 Haas, D.J., and Rossmann, M.G.
Crystallographic Studies on Lactate Dehydrogenase at -75 C. Acta Crystallogr. (1970), B26, 998.
References
- ^ Hope H (1988). "Cryocrystallography of biological macromolecules: a generally applicable method". Acta Crystallogr. B. 44 (1): 22–26. doi:10.1107/s0108768187008632. PMID 3271102.