Sawyer Gregory A, Frederick Elizabeth D, Millard Julie T
Department of Chemistry, 5757 Mayflower Hill Drive, Colby College, Waterville, Maine 04901, USA.
Chem Res Toxicol. 2004 Aug;17(8):1057-63. doi: 10.1021/tx0499057.
Diepoxybutane, diepoxyoctane, and mechlorethamine are cytotoxic agents that induce interstrand cross-links between the N7 positions of deoxyguanosine residues on opposite strands of the DNA duplex preferentially at 5'-GNC sequences. We have systematically varied the identity of either the base 5' to the cross-linked deoxyguanosine residues or the intervening base pair to determine flanking sequence effects on cross-linking efficiency. We used synthetic DNA oligomers containing four 5'-N(1)GN(2)C sites that varied either N(1) or N(2). Interstrand cross-links were purified through denaturing polyacrylamide gel electrophoresis and then subjected to piperidine cleavage. The amount of cleavage at each deoxyguanosine residue, representative of cross-linking efficiency at that site, was determined by sequencing gel analysis. Our data suggest that cross-linking efficiency varies with the identity of N(1) similarly (purines > pyrimidines) for diepoxybutane, diepoxyoctane, and mechlorethamine but that the effects of N(2) differ for the three compounds.
1,4 - 丁二醇二缩水甘油醚、1,8 - 辛二醇二缩水甘油醚和氮芥是细胞毒性剂，它们优先在5'-GNC序列处诱导DNA双链体相反链上脱氧鸟苷残基的N7位之间形成链间交联。我们系统地改变了交联脱氧鸟苷残基5'端碱基或中间碱基对的身份，以确定侧翼序列对交联效率的影响。我们使用了含有四个5'-N(1)GN(2)C位点的合成DNA寡聚物，其中N(1)或N(2)有所不同。通过变性聚丙烯酰胺凝胶电泳纯化链间交联，然后进行哌啶切割。通过测序凝胶分析确定每个脱氧鸟苷残基处的切割量，该切割量代表该位点的交联效率。我们的数据表明，对于1,4 - 丁二醇二缩水甘油醚、1,8 - 辛二醇二缩水甘油醚和氮芥，交联效率随N(1)的身份变化类似（嘌呤>嘧啶），但N(2)对这三种化合物的影响不同。
