Shida T, Noda M, Sekiguchi J
Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan.
Nucleic Acids Symp Ser. 1995(34):87-8.
The major apurinic/apyrimidinic (AP) DNA-repair endonuclease of Escherichia coli is the endonuclease VI (exonuclease III) protein. To elucidate the substrate specificity of the AP endonuclease, we used the double- and single-stranded oligo deoxyribonucleotides containing an AP residue such as 2-deoxyribosylformamide (1), 2-deoxyribose (2), 1,2-dideoxyribofuranose (3), and propanediol (4) as the substrate. The endonuclease VI cleaved the phosphodiester bond 5' at these AP sites of the duplexes. The endonucleolytic activity was not influenced by the kind of nucleotide residue on the opposite side of the AP site. Further, it was observed that the AP endonuclease cleaved single-stranded oligomers containing an AP site.
大肠杆菌主要的脱嘌呤/脱嘧啶（AP）DNA修复内切核酸酶是内切核酸酶VI（外切核酸酶III）蛋白。为阐明AP内切核酸酶的底物特异性，我们使用了含有AP残基的双链和单链寡脱氧核糖核苷酸作为底物，如2-脱氧核糖甲酰胺（1）、2-脱氧核糖（2）、1,2-二脱氧核糖呋喃糖（3）和丙二醇（4）。内切核酸酶VI在双链体的这些AP位点5'处切割磷酸二酯键。内切核酸酶活性不受AP位点另一侧核苷酸残基种类的影响。此外，还观察到AP内切核酸酶可切割含有AP位点的单链寡聚物。
