title: Crystallization and preliminary X-ray crystallographic analysis of the N-terminal photosensory module of phytochrome Agp1, a biliverdin-binding photoreceptor from Agrobacterium tumefaciens.
abstract: Phytochromes are photochromic photoreceptors with a bilin chromophore that have been found in plants and bacteria. Typical bacterial phytochromes are composed of an N-terminal photosensory chromophore module and a C-terminal protein kinase. The former contains the chromophore, which allows phytochromes to adopt the two interconvertible spectral forms, Pr and Pfr. The N-terminal photosensory module of Agrobacterium phytochrome Agp1, Agp1-M15, was used for crystallization studies. The protein was either assembled with the natural chromophore biliverdin or a sterically locked synthetic biliverdin-derivative, termed 15Za. The last-named adduct does not undergo photoisomerization due to an additional carbon chain between the rings C and D of the chromophore. Both adducts could be crystallized, but the resolution was largely improved by the use of 15Za. Crystals of biliverdin-Agp1-M15 diffract to 6A resolution and belong to the tetragonal space group I422 with unit cell dimensions a = b = 171 Angstroms, c = 81 Angstroms, crystals of 15Za-Agp1-M15 belong to the same space group with similar unit cell dimensions a = b = 174 Angstroms, c = 80 Angstroms, but diffract to 3.4 Angstroms resolution. Assuming the asymmetric unit to be occupied by one monomer of 55kDa, the unit cell contains 54-55% solvent with a crystal volume per protein mass, V(m), of 2.7 Angstroms(3) Da(-1).
authors.affiliation: Charité-Universitätsmedizin Berlin, Institut für Biochemie, Proteinstrukturforschung, Campus Charité-Mitte, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Scheerer
authors.forename: Norbert
authors.initials: N
authors.lastname: Michael
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Park
authors.forename: Steffi
authors.initials: S
authors.lastname: Noack
authors.forename: Charlotte
authors.initials: C
authors.lastname: Förster
authors.forename: Mostafa A S
authors.initials: MA
authors.lastname: Hammam
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Inomata
authors.forename: Hui-Woog
authors.initials: HW
authors.lastname: Choe
authors.forename: Tilman
authors.initials: T
authors.lastname: Lamparter
authors.forename: Norbert
authors.initials: N
authors.lastname: Krauss
mesh_terms: D016960:Agrobacterium tumefaciens; D001426:Bacterial Proteins / Q000737:chemistry*; D001664:Biliverdine / Q000737:chemistry / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D020283:Photoreceptors, Microbial / Q000737:chemistry*; D010834:Phytochrome / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; D010834:Phytochrome; D001664:Biliverdine