Silver clusters as both chromophoric reporters and DNA ligands.
Silver clusters as both chromophoric reporters and DNA ligands.
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DOI：
10.1021/ac303531y
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发表时间：
2013-02-19
影响因子：
7.4
通讯作者：
Story SP
中科院分区：
文献类型：
--
作者：
Petty JT;Giri B;Miller IC;Nicholson DA;Sergev OO;Banks TM;Story SP
与 DNA 结合的分子银簇充当分析物传感器。我们的研究评估了一种充满簇的 DNA 链，其结构和银化学计量随着杂交而变化。该传感器链集成了两种功能：3'区域通过碱基识别结合目标DNA链，而5'序列C3AC3AC3TC3A有利于形成近红外吸收和发射簇。这种前体形式专门含有约 11 个银原子簇，可吸收 400 nm 波长并凝聚其单链主体。 3' 识别位点与互补目标链结合，从而影响簇吸收的 330 nm 红移和 790 nm 簇发射的背景限制恢复。这些变化背后的因素之一是传感器的展开和聚合。盐和寡核苷酸浓度的变化通过影响 DNA 缔合来控制簇的发育。使用荧光各向异性、荧光相关光谱和尺寸排阻色谱进行的结构研究表明，传感器-簇缀合物打开并随后通过杂交二聚化。造成光谱和光物理变化的第二个因素是簇转变。经验性的银化学计量通过杂交得以保留，因此杂交的二聚体近红外缀合物的银含量是其紫光吸收前体的两倍。这些 DNA 结构和净银化学计量的改变让我们深入了解 DNA-银缀合物如何识别分析物。
Molecular silver clusters conjugated with DNA act as analyte sensors. Our studies evaluate a type of cluster-laden DNA strand whose structure and silver stoichiometry changes with hybridization. The sensor strand integrates two functions: the 3′ region binds target DNA strands through base recognition while the 5′ sequence C3AC3AC3TC3A favors formation of a near infrared absorbing and emitting cluster. This precursor form exclusively harbors an ~11 silver atom cluster that absorbs at 400 nm and that condenses its single-stranded host. The 3′ recognition site associates with a complementary target strand, thereby effecting a 330 nm red-shift in cluster absorption and a background-limited recovery of cluster emission at 790 nm. One factor underlying these changes is sensor unfolding and aggregation. Variations in salt and oligonucleotide concentrations control cluster development by influencing DNA association. Structural studies using fluorescence anisotropy, fluorescence correlation spectroscopy, and size exclusion chromatography show that the sensor-cluster conjugate opens and subsequently dimerizes with hybridization. A second factor contributing to the spectral and photophysical changes is cluster transformation. Empirical silver stoichiometries are preserved through hybridization, so hybridized, dimeric near infrared conjugates host twice the amount of silver in relation to their violet absorbing predecessors. These DNA structure and net silver stoichiometry alterations provide insight into how DNA-silver conjugates recognize analytes.