Crystallization and evaluation of hen egg-white lysozyme crystals for protein pH titration in the crystalline state.
To observe the ionized status of the amino acid residues in proteins at different pH (protein pH titration in the crystalline state) by neutron diffraction, hen egg-white lysozyme was crystallized over a wide pH range (2.5-8.0). Crystallization phase diagrams at pH 2.5, 6.0 and 7.5 were determined. At pH < 4.5 the border between the metastable region and the nucleation region shifted to the left (lower precipitant concentration) in the phase diagram, and at pH > 4.5 the border shifted to the right (higher precipitant concentration). The qualities of these crystals were characterized using the Wilson plot method. The qualities of all crystals at different pH were more or less equivalent (B-factor values within 25-40). It is expected that neutron diffraction analysis of these crystals of different pH provides equivalent data in quality for discussions of protein pH titration in the crystalline state of hen egg-white lysozyme.
Iwai
Wakari
W
Institute of Applied Beam Science, Graduate School of Science and Engineering, Ibaraki University, Hitachi, Ibaraki 316-8511, Japan.
Yagi
Daichi
D
Ishikawa
Takuya
T
Ohnishi
Yuki
Y
Tanaka
Ichiro
I
Niimura
Nobuo
N
D000818:Animals; D002645:Chickens; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D009113:Muramidase / Q000737:chemistry*; D009502:Neutrons
D009113:Muramidase