Svoboda D L, Taylor J S, Hearst J E, Sancar A
Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599.
J Biol Chem. 1993 Jan 25;268(3):1931-6.
Using a human cell-free extract, we have recently shown that thymine dimers are removed from DNA in oligonucleotides 27-29 nucleotides in length (Huang, J. C., Svoboda, D. L., Reardon, J. T., and Sancar, A. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 3664-3668). In this study we find that the excision reaction is dependent on ATP, the excised fragments range in length from 27-32 nucleotides, and have 5'-P and 3'-OH termini. We also found that a thymine-psoralen furan side monoadduct is excised from the DNA with a similar incision pattern, indicating that in humans bulky adducts are removed from DNA by the same enzyme system which hydrolyzes mainly the 22-24th and the 5th phosphodiester bonds 5' and 3', respectively, to the lesion. This incision pattern might be common to eukaryotic excision nucleases as thymine dimers were removed from DNA by the same dual incision pattern by Xenopus laevis oocytes.
我们最近利用人无细胞提取物证明，长度为27 - 29个核苷酸的寡核苷酸中的胸腺嘧啶二聚体可从DNA中去除（黄，J.C.，斯沃博达，D.L.，里尔登，J.T.，和桑卡尔，A.（1992年）美国国家科学院院刊89，3664 - 3668）。在本研究中，我们发现切除反应依赖于ATP，切除的片段长度在27 - 32个核苷酸之间，并且具有5'-P和3'-OH末端。我们还发现胸腺嘧啶-补骨脂素呋喃侧单加合物以类似的切口模式从DNA中切除，这表明在人类中，大分子加合物通过相同的酶系统从DNA中去除，该酶系统分别主要水解损伤位点5'和3'方向的第22 - 24个和第5个磷酸二酯键。这种切口模式可能是真核切除核酸酶所共有的，因为非洲爪蟾卵母细胞通过相同的双切口模式从DNA中去除胸腺嘧啶二聚体。
