Johnston B H, Rich A
Cell. 1985 Oct;42(3):713-24. doi: 10.1016/0092-8674(85)90268-5.
Chemical probes sensitive to alterations in DNA conformation, especially Z-DNA, have been identified. These permit cleavage of DNA at sites of unusual structure, the results of which can be displayed on a sequencing gel. Using supercoiled plasmids containing inserts of d(C-G)16 and d(C-A)31 X d(T-G)31, it was found that hydroxylamine and osmium tetraoxide react preferentially with cytosines and thymines, respectively, near B-DNA-Z-DNA junctions; diethylpyrocarbonate reacts more strongly with purines within Z-DNA regions; and dimethylsulfate and diethylsulfate react more strongly with guanines in Z-DNA that are out of phase with the usual pattern of purine-pyrimidine alternation. Our results show that B-Z boundaries are mobile and that with increasing torsional strain, the Z-DNA regions can expand to include nonalternating nucleotide sequences.
已鉴定出对DNA构象变化敏感的化学探针，尤其是对Z-DNA敏感的探针。这些探针可在异常结构位点切割DNA，其结果可在测序凝胶上显示。使用含有d(C-G)16和d(C-A)31×d(T-G)31插入片段的超螺旋质粒，发现羟胺和四氧化锇分别优先与B-DNA-Z-DNA交界处附近的胞嘧啶和胸腺嘧啶反应；焦碳酸二乙酯与Z-DNA区域内的嘌呤反应更强；硫酸二甲酯和硫酸二乙酯与Z-DNA中与嘌呤-嘧啶交替的通常模式不同步的鸟嘌呤反应更强。我们的结果表明，B-Z边界是可移动的，并且随着扭转应变的增加，Z-DNA区域可以扩展以包括非交替核苷酸序列。
