Cryo bio-crystallography explained

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.pdf1970 Haas, D.J., and Rossmann, M.G. Crystallographic Studies on Lactate Dehydrogenase at -75 C. Acta Crystallogr. (1970), B26, 998.

See also

• X-ray crystallography
• Cryo-EM
• Ada Yonath

Notes and References

1. Hope H . Cryocrystallography of biological macromolecules: a generally applicable method. Acta Crystallogr. B. 44 . 1 . 22–26 . 1988 . 3271102 . 10.1107/s0108768187008632.