Lack of Z-DNA conformation in mitomycin-modified polynucleotides having inverted circular dichroism.
Lack of Z-DNA conformation in mitomycin-modified polynucleotides having inverted circular dichroism.
复制标题
具有倒圆二色性的丝裂霉素修饰的多核苷酸中缺乏Z-DNA构象。
DOI：
10.1073/pnas.80.10.2874
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发表时间：
1983
影响因子：
11.1
通讯作者：
Stollar,BD
中科院分区：
文献类型：
--
作者：
Tomasz,M;Barton,JK;Magliozzo,CC;Tucker,D;Lafer,EM;Stollar,BD
Poly(dG-dC) . poly(dG-dC) and Micrococcus lysodeikticus DNA were modified by exposure to reductively activated mitomycin C, an antitumor antibiotic. The resulting covalent drug-polynucleotide complexes displayed varying degrees of CD inversions, which are strikingly similar to the inverted spectrum observed with Z-DNA. The following criteria have been used to establish, however, that the inverted CD pattern seen in mitomycin C-polynucleotide complexes does not reflect a Z-DNA conformation. (i) The ethanol-induced transition of poly(dG-dC) . poly(dG-dC) from B to Z conformation is not facilitated but rather is inhibited by mitomycin C modification. This may be due to the presence of crosslinks, (ii) Radioimmunoassay indicated no competition for Z-DNA-specific antibody by any of the mitomycin C-modified polynucleotides, (iii) 31P NMR of the complexes yielded a single relatively narrow resonance, which is inconsistent with the dinucleotide repeat characteristic of Z-DNA. Alternative explanations for the inverted CD pattern include a drug-induced left-handed but non-Z conformational change or the superposition of an induced CD onto the CD of B-DNA due to drug-base electronic interactions. These results illustrate the need for caution in interpreting CD changes alone as an indication of Z-DNA conformation.
