MOLECULAR BASIS OF CONTROL IN THE L-ARABINOSE OPERON

遗传和生物化学实验进行了描述，将分析 控制L-阿拉伯糖操纵子表达的分子相互作用， 大肠埃希菌 araBAD操纵子和araC调控基因启动子 将用体外诱变使突变体饱和。 的方法 所用的方法包括（1）合成的阿托西肽定向诱变，（2） 用羟胺重诱变，和（3）定点化学 改性 在体外产生的突变将被转移到 染色体上，用于分析它们对ara基因表达的影响。 编码的推定多肽的可能的功能意义 将评估araC前导mRNA。 将在DNA上进行比较 ara启动子和来自其他来源的araC基因的序列水平 肠杆菌科 小分子与纯化araC的相互作用 将通过荧光分光光度法研究调节蛋白。 最后，将尝试确定三维结构 有和没有L-阿拉伯糖和araC的araC调节蛋白 与araO和araO DNA复合的蛋白质。

Genetic and biochemical experiments are described which will analyze the molecular interactions that control expression of the L-arabinose operon in Escherichia coli. The araBAD operon and araC regulatory gene promoters will be saturated with mutants using in vitro mutagenesis. The methods used will include (1) synthetic oligonucleotide-directed mutagenesis, (2) heavy mutagenesis with hydroxylamine, and (3) site-directed chemical modification. Mutations created in vitro will be transferred to the chromosome for analysis of their effect on expression of the ara genes. The possible functional significance of a putative polypeptide coded for by araC leader mRNA will be assessed. A comparison will be made at the DNA sequence level of ara promoters and the araC gene from other Enterobacteriaceae. The interaction of small molecules with purified araC regulatory protein will be studied by spectrofluorimetric methods. Finally, an attempt will be made to determine the 3-dimensional structure of the araC regulatory protein with and without L-arabinose and araC protein complexed with araI and araO DNA.