Zimmer C, Tymen S, Marck C, Guschlbauer W
Nucleic Acids Res. 1982 Feb 11;10(3):1081-91. doi: 10.1093/nar/10.3.1081.
Poly(dA-dC).poly(dG-dT) was studied by circular dichroism in the presence of high CsCl concentrations and in ethanolic solutions. This alternating purine-pyrimidine duplex may undergo two conformational transitions from a B-type to a novel structure and subsequently into an A-form. Cs+ ions or increasing ethanol concentrations induced a change of the B-type CD spectrum and an inversion of the long wavelength CD band. Lowering the temperature below 0 C or addition of small amounts of Ca++ ions were particularly potent in producing a large negative CD band. A modified B-type structure or a conversion into a left-handed Z-form is considered for this conformational transition.
在高浓度氯化铯存在的情况下以及在乙醇溶液中,通过圆二色性对聚(dA-dC)·聚(dG-dT)进行了研究。这种交替的嘌呤-嘧啶双链体可能经历从B型到一种新结构,随后再转变为A型的两种构象转变。铯离子或乙醇浓度的增加会导致B型圆二色光谱发生变化以及长波长圆二色带发生反转。将温度降低至0℃以下或添加少量钙离子在产生大的负圆二色带方面特别有效。这种构象转变被认为是形成了一种修饰的B型结构或转变为左手Z型。