Light-induced conformational changes of the chromophore and the protein in phytochromes: bacterial phytochromes as model systems.
Recombinant phytochromes Agp1 and Agp2 from Agrobacterium tumefaciens are used as model phytochromes for biochemical and biophysical studies. In biliverdin binding phytochromes the site for covalent attachment of the chromophore lies in the N-terminal region of the protein, different from plant phytochromes. The issue which stereochemistry the chromophore adopts in the so-called Pr and Pfr forms is addressed by using a series of locked chromophores which form spectrally characteristic adducts with Agp1 and Agp2. Studies on light-induced conformational changes of Agp1 give an insight into how the intrinsic histidine kinase is modulated by light. Comparison of the crystal structure of an Agp1 fragment with other phytochrome crystal structures supports the idea that a light induced rearrangement of subunits within the homodimer modulates the activity of the kinase.
Scheerer
Patrick
P
Institut für Medizinische Physik und Biophysik (CC2), Charité-Universitätsmedizin Berlin, Ziegelstr. 5-9, D-10117 Berlin, Germany.
Michael
Norbert
N
Park
Jung Hee
JH
Nagano
Soshichiro
S
Choe
Hui-Woog
HW
Inomata
Katsuhiko
K
Borucki
Berthold
B
Krauss
Norbert
N
Lamparter
Tilman
T
D016960:Agrobacterium tumefaciens / Q000201:enzymology; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019143:Evolution, Molecular; D000071677:Histidine Kinase; D008027:Light; D010834:Phytochrome / Q000737:chemistry* / Q000145:classification; D011494:Protein Kinases / Q000737:chemistry*; D017434:Protein Structure, Tertiary
D010834:Phytochrome; D011494:Protein Kinases; D000071677:Histidine Kinase