Abstract:

By using the liquid/liquid diffusion method at a suitable crystallization conditions, large single and dark brown crystals (the sides of the largest crystals were 0.20 mm×0.20 mm×0.07 mm and 0.18 mm×0.18 mm×0.05 mm, respectively) could be obtained from the solutions of nitrogenase CrFe protein and MnFe protein purified from a mutant UW3 of Azotobacter vinelandii Lipmann grown in Cr- or Mn-containing but NH3-free medium. The time of crystal formation, as well as the number,size, shape and quality of crystals obviously depended on the concentrations of PEG, MgCl2 and NaCl. The liquid/liquid diffusion method seems to benefit CrFe protein and MnFe protein for the growth of large single crystals for X-ray diffraction analysis. Key words: mutant UW3 of Azotobacter vinelandii; nitrogenase CrFe protein and MnFe protein; growth of large single crystals

固氮酶铬铁蛋白和锰铁蛋白大单晶的培养
吕玉兵  赵 颖  赵剑峰  代小虎  仓怀兴  王耀萍 黄巨富

（1. 中国科学院植物研究所光合作用与环境分子生理学重点实验室，北京100093；2. 中国科学院生物物理研究所，北京100101）

摘要： 用液／液扩散法，从分别含Cr和Mn的无氨培养基中生长的固氮菌（Azotobacter vinelandii Lipmann)突变种UW₃中纯化出的CrFe蛋白和MnFe蛋白，在合适的结晶条件下生长出深棕色大单晶（最大晶体的尺寸分别为0．20mm×0．20mm×0．07mm和0．18mm×0．18mm×0．05mm）。PEG、MgCl₂和NaCl的浓度对这两种蛋白的出晶时间、晶核数目、晶体大小和形状都有明显影响。结果表明，用此结晶法有利于CrFe蛋白和MnFe蛋白生长出可供X－射线衍射分析的大单晶。

关键词： 棕色固氮菌突变种UW₃；固氮酶铬铁蛋白和锰铁蛋白；大单晶生长