Sharp melting transitions in DNA hybrids without aggregate dissolution: Proof of neighboring-duplex cooperativity
Sharp melting transitions in DNA hybrids without aggregate dissolution: Proof of neighboring-duplex cooperativity
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DOI：
10.1021/ja073034g
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发表时间：
2007-12-19
影响因子：
15
通讯作者：
Nguyen, SonBinh T.
中科院分区：
文献类型：
--
作者：
Gibbs-Davis, Julianne M.;Schatz, George C.;Nguyen, SonBinh T.
与DNA修饰的金纳米颗粒类似，梳状聚合物-DNA杂化物表现出非常急剧的熔化转变，可用于高选择性DNA检测系统。目前的理论表明，这种急剧的融化是由聚集体的宏观溶解或相邻DNA双链之间紧密堆积环境中相邻双链相互作用引起的相变引起的。为了描述每种效应的作用，设计了一个基于聚合物- dna杂交体的聚合体系，其中包括聚合物连接的和部分非连接的双链体。当这种杂化体系进行热分析时，两种类型的双相都表现出急剧的熔化转变。部分不受束缚的DNA双链所显示的非常急剧的融化转变证明了邻近双链的相互作用确实可以诱导合作。这种相邻双工效应的贡献，以及在聚合物- dna聚集体中观察到的增强的稳定性，可以使用简单的热力学模型进行定量评估。虽然邻近双工相互作用本身可以导致协同熔化，但在聚合物- dna聚集体中观察到的增强稳定性是邻近双工相互作用和多价或聚集体性质的作用。
Similar to DNA-modified gold nanoparticles, comb polymer-DNA hybrids exhibit very sharp melting transitions that can be utilized in highly selective DNA detection systems. Current theories suggest that such sharp melting results from either a phase transition caused by the macroscopic dissolution of the aggregate or neighboring-duplex interactions in the close-packed environment between adjacent DNA duplexes. To delineate the contributions of each of these effects, an aggregate system based on polymer-DNA hybrids was designed to include both polymer-linked and partially untethered duplexes. When this hybridized system was subjected to thermal analysis, both types of duplexes exhibited sharp melting transitions. The very sharp melting transition displayed by the partially untethered DNA duplexes offers proof that neighboring-duplex interactions can indeed induce cooperativity. Contributions of this neighboring-duplex effect, as well as the enhanced stabilization observed-in polymer-DNA: polymer-DNA aggregates, can be quantitatively assessed using a simple thermodynamic model. While neighboring-duplex interactions alone can lead to cooperative melting, the enhanced stabilization observed in polymer-DNA aggregates is a function of both neighboring-duplex interactions and multivalent or aggregate properties.