TY - JOUR
T1 - Interactions in solution and crystallization of Aspergillus flavus urate oxidase
AU - Bonnete, Francoise
AU - Vivares, Denis
AU - Robert, Christelle
AU - Colloc'h, N.
PY - 2001/8/15
Y1 - 2001/8/15
N2 - Interparticle interactions of urate oxidase from Aspergillus flavus have been studied by small-angle X-ray scattering to determine crystallization conditions. This enzyme is a homotetramer with a total molecular weight of 128 kDa. It is a slightly basic protein (pI between 7.5 and 8). The interaction potentials have been studied as a function of the main thermodynamic and chemical parameters: temperature, protein concentration, pH, salt nature and concentration, addition of polyols. In 10 mM sodium carbonate at pH 10.5, the interactions are slightly repulsive and become less repulsive with a pH closer to pI. With the addition of carbonate, the protein loses its tetrameric structure for a dimeric one; with formate, the tetrameric structure remains stable. We also studied the effect of polyethylene glycols as it had been done with high molecular weight proteins. With the addition of PEG 8 K, the interactions became less repulsive and even turned attractive with the addition of both PEG 8 K and salt. Protein crystals of urate oxidase were observed in slightly repulsive conditions (second virial coefficient A2 about +10−5 mol ml g−2 instead of –2 to –8×10−4 mol ml g−2 for low molecular weight proteins).
AB - Interparticle interactions of urate oxidase from Aspergillus flavus have been studied by small-angle X-ray scattering to determine crystallization conditions. This enzyme is a homotetramer with a total molecular weight of 128 kDa. It is a slightly basic protein (pI between 7.5 and 8). The interaction potentials have been studied as a function of the main thermodynamic and chemical parameters: temperature, protein concentration, pH, salt nature and concentration, addition of polyols. In 10 mM sodium carbonate at pH 10.5, the interactions are slightly repulsive and become less repulsive with a pH closer to pI. With the addition of carbonate, the protein loses its tetrameric structure for a dimeric one; with formate, the tetrameric structure remains stable. We also studied the effect of polyethylene glycols as it had been done with high molecular weight proteins. With the addition of PEG 8 K, the interactions became less repulsive and even turned attractive with the addition of both PEG 8 K and salt. Protein crystals of urate oxidase were observed in slightly repulsive conditions (second virial coefficient A2 about +10−5 mol ml g−2 instead of –2 to –8×10−4 mol ml g−2 for low molecular weight proteins).
U2 - 10.1016/S0022-0248(01)01054-5
DO - 10.1016/S0022-0248(01)01054-5
M3 - Article
SN - 0022-0248
JO - JOURNAL OF CRYSTAL GROWTH
JF - JOURNAL OF CRYSTAL GROWTH
ER -