Stabilization of triple-helical nucleic acids by basic oligopeptides.
Stabilization of triple-helical nucleic acids by basic oligopeptides.
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DOI：
10.1021/bi00045a033
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发表时间：
1995-11
期刊：
影响因子：
2.9
通讯作者：
V. Potaman;R. Sinden
中科院分区：
文献类型：
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作者：
V. Potaman;R. Sinden
分子间三链 DNA 通过金属阳离子和多胺来稳定，从而减少三个核酸链带负电荷的磷酸盐之间的排斥力。我们使用定量化学探测分析来研究碱性寡肽对三链体 DNA 稳定性的影响，其中涉及保护来自硫酸二甲酯修饰的同型嘧啶.同型嘌呤 (Py.Pu) 序列中的双链体鸟嘌呤。在 pH 5 时，分子间质子化的嘧啶.嘌呤.嘧啶 (Py.Pu*Py) 三链体很容易在双链体 DNA 区域和 14 聚体嘧啶三链体形成寡核苷酸 (TFO) 之间形成。通过添加镁离子，三链体在 pH 值下稳定。在精胺和富含赖氨酸的肽存在下，分子间三链体的 pH 值稳定在 6.5-7.0。稳定所需的有效肽浓度为10(-5)-10(-2) M。在所研究的碱性肽中，五赖氨酸(Lys-Lys-Lys-Lys-Lys)是最有效的三重稳定剂。它在低于 Lys-Gly-Lys-Gly-Lys 和 Lys-Ala-Lys-Ala-Lys 所需浓度且与精胺活性浓度相似的浓度下有效。碱性肽在稳定 Py.Pu*Py 三链体方面比嘧啶.嘌呤.嘌呤 (Py.Pu*Pu) 三链体更有效。在 1 mM 时，Lys-Lys-Lys-Lys-Lys 使 Py.Pu*Pu 三链体稳定在与 Mn2+ 和精胺的稳定水平相当的水平，而 Lys-Gly-Lys-Gly-Lys 和 Lys-Ala-Lys-Ala-Lys 导致 TFO 结合较弱。在肽存在的情况下，形成三链体 DNA 所需的 TFO 浓度显着降低。（摘要截断为 250 字）
Intermolecular triplex DNA is stabilized by metal cations and polyamines which reduce repulsion between the negatively charged phosphates of the three nucleic acid strands. We use a quantitative chemical-probing assay involving protection of duplex guanines in a homopyrimidine.homopurine (Py.Pu) sequence from dimethyl sulfate modification to study effects of basic oligopeptides on the stability of triplex DNA. An intermolecular protonated pyrimidine.purine.pyrimidine (Py.Pu*Py) triplex formed readily between a duplex DNA region and a 14-mer pyrimidine triplex-forming oligonucleotide (TFO) at pH 5. The triplex was stabilized at pH by the addition of magnesium ions. In the presence of spermine and lysine-rich peptides, the intermolecular triplex was stabilized up to pH 6.5-7.0. The effective peptide concentration required for stabilization was 10(-5)-10(-2) M. Of the basic peptides studied, pentalysine (Lys-Lys-Lys-Lys-Lys) was the most effective triplex stabilizer. It was effective at concentrations which are lower than those required for Lys-Gly-Lys-Gly-Lys and Lys-Ala-Lys-Ala-Lys and are similar to active concentrations of spermine. Basic peptides were more effective at stabilizing a Py.Pu*Py triplex than a pyrimidine.purine.purine (Py.Pu*Pu) triplex. At 1 mM, Lys-Lys-Lys-Lys-Lys stabilized the Py.Pu*Pu triplex at a level comparable to stabilization by Mn2+ and spermine, whereas Lys-Gly-Lys-Gly-Lys and Lys-Ala-Lys-Ala-Lys resulted in weaker TFO binding. The concentration of TFOs required to form triplex DNA were significantly reduced in the presence of peptides.(ABSTRACT TRUNCATED AT 250 WORDS)