Mirabelli C K, Beattie W G, Huang C H, Prestayko A W, Crooke S T
Cancer Res. 1982 Apr;42(4):1399-404.
We have investigated the site-specific cleavage of DNA by the antitumor antibiotics talisomycin and bleomycin by using 5'- or 3'-terminal 32P-labeled restriction fragments of pBR 322 DNA. Both drugs cleaved DNA preferentially at G-C and G-T sequences. However, the relative amounts of cleavage at particular cleavage sites differed between talisomycin and bleomycin at concentrations of the drugs which produced similar extents of total cleavage. In addition, talisomycin produced specific cleavages at G-A sequences which were relatively resistant to cleavage by bleomycin. Within a preferred sequence group (i.e., G-C sequences), some sites were cleaved to a greater extent relative to others by both talisomycin and bleomycin, suggesting that a greater degree of specificity than that provided by only two nucleotides is involved in the site-specific recognition and cleavage of DNA by these drugs.
我们利用pBR 322 DNA的5'-或3'-末端32P标记的限制性片段，研究了抗肿瘤抗生素他利霉素和博来霉素对DNA的位点特异性切割。两种药物都优先在G-C和G-T序列处切割DNA。然而，在产生相似总切割程度的药物浓度下，他利霉素和博来霉素在特定切割位点的相对切割量有所不同。此外，他利霉素在G-A序列处产生特异性切割，而这些序列对博来霉素的切割相对抗性。在一个优选的序列组（即G-C序列）内，一些位点相对于其他位点被他利霉素和博来霉素切割的程度更高，这表明这些药物对DNA的位点特异性识别和切割涉及比仅由两个核苷酸提供的更高程度的特异性。
