Dwelling in the dark: procedures for the crystallography of phytochromes and other photochromic proteins
Photoreceptor crystals are sensitive to light irradiation and tend to diffract poorly. An efficient and inexpensive method is presented to manipulate photochromic proteins in complete darkness using infrared equipment. The proposed set-up, in combination with the use of appropriate cryo-protection and cryo-annealing, allowed not only the structure solution of the complete sensory domain of a cyanobacterial phytochrome at 2.45 Å resolution, but also the potential to be easily adjusted to accommodate the demands of other light-sensitive proteins.
J. Mailliet, G. Psakis, C. Schroeder, S. Kaltofen, U. Dürrwang, J. Hughes and L.-O. Essen
![[IR set-up to observe phytochrome crystals]](https://www.iucr.org/__data/assets/image/0007/28591/ActaD.jpg)
Schematic and photographic view of the simple infrared set-up to observe and freeze phytochrome crystals
