Crystallization and preliminary X-ray crystallographic analysis of the N-terminal photosensory module of phytochrome Agp1, a biliverdin-binding photoreceptor from Agrobacterium tumefaciens.
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).
Scheerer
Patrick
P
Charité-Universitätsmedizin Berlin, Institut für Biochemie, Proteinstrukturforschung, Campus Charité-Mitte, Germany.
Michael
Norbert
N
Park
Jung Hee
JH
Noack
Steffi
S
Förster
Charlotte
C
Hammam
Mostafa A S
MA
Inomata
Katsuhiko
K
Choe
Hui-Woog
HW
Lamparter
Tilman
T
Krauss
Norbert
N
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
D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; D010834:Phytochrome; D001664:Biliverdine