RIBONUCLEASE AND ITS INHIBITOR FROM BACILLUS AMYLOLIQUENFACIENS

芽孢杆菌的胞外核糖核酸酶Barnase 淀粉分解酶和其胞内抑制物Barstar被使用 作为研究蛋白质折叠的模型系统，蛋白质- 蛋白质的相互作用。Barnase是一个同源基团之一 存在于原核生物和真核生物中的核糖核酸酶。 重组DNA技术正被应用于该项目 有三个主要目标：1)促进生产，2)审查 基因的结构和控制序列以及3)剪裁 在序列中专门设计修改以进行测试 蛋白质折叠理论。 克隆的野生型Barnase基因对E. Coli或B.subtilis可被克隆的表达所抑制 Barstar基因位于同一质粒上。分泌载体的研究 这两种蛋白质都已经被设计出来了。 这两个基因都已经测序，证实了 Barnase序列(110个残基)和衍生序列(89 残基)，这与以前的氨基酸非常一致 分析。 几种Barnase定点突变对酶活性的影响 和热稳定性进行了研究。

Two proteins, barnase, the extracellular ribonuclease of Bacillus amyloliquefaciens, and barstar, its intracellular inhibitor, are used as a model system for the study of protein folding a protein- protein interactions. Barnase is one of an homologous group of ribonucleases occurring in both prokaryotes and eukaryotes. Recombinant DNA techniques are being applied to the project with three major aims: 1) to facilitate production, 2) to examine the structural and control sequences of the genes and 3) to tailor specifically designed modifications in the sequences to test theories of protein folding. The lethal effect of the cloned wild-type barnase gene in either E. coli or B. subtilis can be repressed by expression of the cloned barstar gene placed on the same plasmid. Secretion vectors for both proteins have been devised. Both genes have been sequenced, providing confirmation of the barnase sequence (110 residues) and a derived sequence (89 residues) for barstar which agrees well with previous amino-acid analysis. Effects of several site-directed mutations of barnase on activity and thermal stability have been studied.