Protein crystal X-ray diffraction at room temperature? It seems essentially all protein X-ray diffraction structures are obtained with flash-cooled protein crystals (in a stream of very cold gas). I’m curious if the diffraction pattern would be significantly different from the same crystal at room temperature (from thermal expansion, but not only - it may favor different conformations, and also flash cooling may disorder parts of the crystal). What are some of the reasons that X-ray diffraction uses cooled crystals? Is it possible to do the same experiment with a room temperature crystal? Has this been done before, and what happens?

While protein diffraction data is nowadays most often collected in cryogenic temperatures, the room temperature crystallography also exists and you can find thousands of datasets in the PDB that were collected in 300K. The main reason for cryo-cooling is that it slows down radiation damage.

You can find in-depth discussion of both options in the literature. I just quickly googled it and found two review articles about advantages of cryo- and room temperature crystallography:

Cryo-cooling in macromolecular crystallography: advantages, disadvantages and optimization

Macromolecular room temperature crystallography