Endonucleolytic incision of x-irradiated deoxyribonucleic acid by extracts of Escherichia coli.
Endonucleolytic incision of x-irradiated deoxyribonucleic acid by extracts of Escherichia coli.
复制标题
大肠杆菌提取物对 X 射线照射的脱氧核糖核酸进行核酸内切切割。
DOI：
--
复制
发表时间：
1975
影响因子：
11.1
通讯作者：
S. Wallace
中科院分区：
文献类型：
--
作者：
G. Strniste;S. Wallace
在大肠杆菌提取物中存在与X射线照射的DNA反应的核酸内切酶活性。杆菌通过使用离心方法监测噬菌体phi-x-174（复制型）或PM 2的超螺旋环状双链DNA向松弛环状DNA的转化，可以定量DNA中辐射诱导的核酸内切酶敏感位点的速率。对于在有氧照射条件下由X射线诱导的每个单链断裂，大约有一个诱导位点对此内切核酸酶活性敏感。在照射条件下（加入碘化钾），大大降低率的单链断裂和“碱性”病变，内切酶敏感位点的数量相对于单链断裂增加约4倍。这种核酸酶存在于几种大肠杆菌菌株中。coli B和K12，包括DNA聚合酶I缺陷突变体、重组基因产物（rec突变体）、紫外光切割酶（uvr A突变体）和内切核酸酶II。有人建议，这种核酸内切酶可能参与切除修复过程中所发生的损伤DNA电离辐射。
An enconuclease activity that reacts with x-irradiated DNA is present in extracts of E. coli. By using centrifugal methods to monitor the conversion of the supercoiled, circular double-stranded DNA for phage phi-x-174 (replicative form) or PM2 to the relaxed circular form it was possible to quantitate the rate of radiation induced endonuclease-sensitive sites in the DNA. For every single-strand break induced by x-rays under aerobic irradiation conditions, there is approximately one induced site sensitive to this endonuclease activity. Under irradiation conditions (addition OF Potassium iodide) that dramatically reduce rates of single-strand breaks and "alkalilabile" lesions, the number of endonuclease-sensitive sites relative to single-strand breaks increase approximatley 4-fold. This nuclease is present in several strains of E. coli B and K12, including mutants deficient in DNA polymerase I, recombination gene products (rec mutants), ultraviolet light incision enzyme (uvr A mutant), and endonuclease II. It is suggested that this endonuclease may be involved in an excision repair process for damages incurred in DNA by ionizing radiation.