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Light‐Induced Conformational Changes of the Chromophore and the Protein in Phytochromes: Bacterial Phytochromes as Model Systems
Author(s) -
Scheerer Patrick,
Michael Norbert,
Park Jung Hee,
Nagano Soshichiro,
Choe HuiWoog,
Inomata Katsuhiko,
Borucki Berthold,
Krauß Norbert,
Lamparter Tilman
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900913
Subject(s) - phytochrome , chromophore , biliverdin , histidine kinase , chemistry , conformational change , protein structure , biophysics , histidine , biochemistry , photochemistry , biology , heme , botany , enzyme , red light , heme oxygenase
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.