Riazuddin S, Grossman L
J Biol Chem. 1977 Sep 25;252(18):6287-93.
Py pyrimidine dimers Py correndonucleases I and II from Micrococcus luteus act exclusively on thymine-thymine, cytosine-cytosine, and thymine-cytosine cyclobutyl dimers in DNA, catalyzing incision 5' to the damage and generating 3'-hydroxyl and 5'-phosphoryl termini. Both enzymes initiate excision of pyrimidine dimers in vitro by correxonucleases and DNA polymerase I. The respective incised DNAs, however, differ in their ability to act as substrate for phage T4 polynucleotide ligase or bacterial alkaline phosphatase, suggesting that each endonuclease is specific for a conformationally unique site. The possibility that their respective action generates termini which represent different degrees of single strandedness is suggested by the unequal protection by Escherichia coli binding protein from the hydrolytic action of exonuclease VII.
来自藤黄微球菌的嘧啶二聚体核酸内切酶I和II仅作用于DNA中的胸腺嘧啶-胸腺嘧啶、胞嘧啶-胞嘧啶和胸腺嘧啶-胞嘧啶环丁烷二聚体，催化在损伤位点5'端进行切割，产生3'-羟基和5'-磷酸末端。两种酶在体外均通过核酸外切酶和DNA聚合酶I启动嘧啶二聚体的切除。然而，各自切割后的DNA作为噬菌体T4多核苷酸连接酶或细菌碱性磷酸酶底物的能力不同，这表明每种核酸内切酶对构象独特的位点具有特异性。大肠杆菌结合蛋白对核酸外切酶VII水解作用的不等保护表明，它们各自的作用产生的末端代表不同程度的单链状态。
