Sulfonated Ni(II)porphyrin improves the detection of Z-DNA in condensed and non-condensed BZB DNA sequences

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• 作者：Andrea E. Holmes^a ; Jung Kyu Choi^c ; Jacob Francis^a ; Alessandro D'Urso^a ; ^b ; ^{adurso@unict.it} ; Milan Balaz^c ; ^{mbalaz@uwyo.edu}
• 关键词：Anionic nickel(II) porphyrin ; Left-handed Z-DNA ; BZB sequences ; Induced circular dichroism ; Z-DNA detection
• 刊名：Journal of Inorganic Biochemistry
• 出版年：2012
• 期刊代码：53_01620134
• 类别：ch
• 出版时间：May, 2012
• 卷：110
• 期：Complete
• 页码：18-20
• 文件大小：587 K

摘要

We report a very selective and sensitive spectroscopic detection of Z-DNA embedded in B-DNA in condensed as well as non-condensed DNA using anionic Ni(II) meso-tetrakis(4-sulphonatophenyl)porphyrin, NiTPPS. A combination of micromolar concentrations of Ni(II) and spermine^4 + allowed us to prepare left-handed Z-DNA in short oligonucleotides without DNA condensation. A strong induced circular dichroism (ICD) signal was observed in the visible absorption region when NiTPPS was added to BZ DNA (Z-DNA fragment located at the end of a B-DNA tract with one B/Z DNA junction) and BZB DNA (Z-DNA sequence embedded in B-DNA having two B/Z DNA junctions). Almost no ICD signal was detected when NiTPPS was added to B-DNA. NiTPPS showed different binding modes with condensed and non-condensed Z-DNAs and allowed the distinction between condensed Z-DNA (positive bisignate CD couplet) and non-condensed Z-DNA (negative bisignate CD couplet).