Izaac Aude, Schall Constance A, Mueser Timothy C
Department of Chemistry, The University of Toledo, Toledo, OH 43606, USA.
Acta Crystallogr D Biol Crystallogr. 2006 Jul;62(Pt 7):833-42. doi: 10.1107/S0907444906018385. Epub 2006 Jun 20.
The utility of a preliminary solubility screen has been assessed on ten test proteins. It is proposed that maximizing the protein solubility prior to crystal setups is likely to improve crystal growth. In crystallization setups, drops of a protein solution are mixed with various crystallization solutions which are then allowed to equilibrate. The protein solutions usually contain a salt and buffer which are present as a constant in all crystal screens. The propensity for crystallization, driven by three components of sparse-matrix screens, the buffers, salts and precipitating agents, could potentially be masked by the components of the protein solution. Ten test proteins were dissolved in a standard buffer (100 mM NaCl, 50 mM Tris-HCl pH 7.5) and in customized optimal buffers determined to maximize solubility. The proteins were then subjected to the Index (Hampton Research) 96-well sparse-matrix crystal screen and to a precipitant/precipitant-additive screen described here. Five of the ten proteins studied showed twofold to fourfold increases in the saturation level from standard to optimal buffer, two showed slight improvement and three showed a slight decrease. Microcrystals were obtained for all proteins and optimal buffer increased the appearance of crystals for eight of the ten proteins.
已对十种测试蛋白评估了初步溶解度筛选的效用。有人提出，在进行晶体设置之前使蛋白溶解度最大化可能会改善晶体生长。在结晶设置中，将蛋白溶液的液滴与各种结晶溶液混合，然后使其平衡。蛋白溶液通常含有一种盐和缓冲液，在所有晶体筛选中它们的含量都是恒定的。由稀疏矩阵筛选的三个成分（缓冲液、盐和沉淀剂）驱动的结晶倾向可能会被蛋白溶液的成分所掩盖。将十种测试蛋白溶解在标准缓冲液（100 mM NaCl，50 mM Tris-HCl pH 7.5）和经测定可使溶解度最大化的定制最佳缓冲液中。然后将这些蛋白进行Index（Hampton Research）96孔稀疏矩阵晶体筛选以及此处所述的沉淀剂/沉淀剂添加剂筛选。所研究的十种蛋白中有五种从标准缓冲液到最佳缓冲液的饱和度水平提高了两倍至四倍，两种略有改善，三种略有下降。所有蛋白都获得了微晶，并且最佳缓冲液使十种蛋白中的八种出现了晶体。
