E. Coli Exonuclease VII

外切酶VII是一种单链特异性脱氧核糖核酸酶，可以降解变性DNA，从双链DNA末端延伸的单链区域或移位的单链区域。它由两个不相同的亚基组成，基因位于染色体的不同区域。本文提出表达和纯化大量的酶，研究其产生的细胞调控，并检查其缺乏对细胞的影响。大量酶的可用性将允许开始详细的机制和功能研究。拥有编码这两个亚基的克隆基因使得研究基因的转录调控成为可能。对突变的分析可以进一步了解酶在细胞代谢中的作用。核酸酶是参与核酸代谢的数量最多、种类最多的一类酶。在许多DNA和RNA代谢过程的纸质模型中，这些酶应该发挥的各种功能是非常明显的。事实上，只有少数这种酶在细胞中的作用是被了解的。大肠杆菌外切酶VII则不是。它的酶性质表明它将是一种非常有用的试剂，用于从双链DNA分子中特异性去除单链末端。蔡斯博士是核酸外切酶VII的发现者，他肯定会准备重新开始这项研究。

Exonuclease VII is a single stranded specific deoxynibonuclease which cna degrade denatured DNA, single stranded regions extending from from the termini of duplex DNA, or displaced single stranded regions. It is composed of two non-identical subunits, the genes being in different regions of the chromosome. It is proposed here to express and purify large quanties of the enzyme, study the cellular regulation of its production, and examine the cellular effects of its deficiency. The availability of large quantities of the enzyme will allow detailed mechanistic and functional studies to begin. Having the cloned genes which encode the two subunits makes possible studies of the transcriptional regulation of the genes. The analysis of mutations may provide further insight into the role the enzyme plays in cellular metabolism. Nucleases are among the most abundant and diverse group of enzymes participating in nucleic acid metabolism. It is perfectly obvious in paper models of many DNA and RNA metabolic processes what a variety of functions these enzymes should do. In actual fact, the cellular roles of only a few such enzymes are understood. E. coli exonuclease VII is one that is not. Its enzymatic properties suggest it will be an extremely useful reagent for the specific removal of single-stranded termini from duplex DNA molecules. Dr. Chase was the discoverer of Exonuclease VII and is certainly will prepared to reinitiate this study.