Dwelling in the dark: procedures for the crystallography of phytochromes and other photochromic proteins.
Crystallization of phytochromes and other photochromic proteins is hampered by the conformational changes that they undergo on exposure to light. As a canonical phytochrome, cyanobacterial Cph1 switches between two stable states upon absorption of red/far-red light. Consequently, it is mandatory to work in darkness from protein purification to crystal cryoprotection in order to ensure complete occupancy of one state or the other. With the simple and inexpensive methods that have been developed, phytochromes and other photochromic molecules can effectively be handled and crystallized, as has been demonstrated by the solution of the three-dimensional structure of the Cph1 sensory module.
Mailliet
Jo
J
Justus Liebig University Giessen, Plant Physiology, D-35390 Giessen, Germany.
Psakis
Georgios
G
Schroeder
Claudia
C
Kaltofen
Sabine
S
Dürrwang
Ulrike
U
Hughes
Jon
J
Essen
Lars Oliver
LO
D001426:Bacterial Proteins / Q000032:analysis* / Q000737:chemistry; D003460:Crystallization; D000458:Cyanobacteria / Q000737:chemistry*; D003624:Darkness; D020283:Photoreceptors, Microbial; D010834:Phytochrome / Q000032:analysis* / Q000737:chemistry; D011494:Protein Kinases / Q000032:analysis* / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000379:methods*; D014961:X-Ray Diffraction / Q000379:methods*
D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; D010834:Phytochrome; D011494:Protein Kinases; C413623:Cph1 phytochrome protein, bacteria