For the first time, a metal-mediated base pair has been used to modulate the affinity of an aptamer towards its target. In particular, two artificial imidazole 2’-deoxyribonucleosides (Im) were incorporated into various positions of an established ATP-binding aptamer (ATP, adenosine triphosphate), resulting in the formation of three aptamer derivatives bearing Im:Im mispairs with a reduced ATP affinity. A fluorescence spectroscopy assay and a binding assay with immobilized ATP were used to evaluate the aptamer derivatives. Upon the addition of one Ag(I) ion per mispair, stabilizing Im–Ag(I)–Im base pairs were formed. As a result, the affinity of the aptamer derivative towards ATP is restored again. The silver(I)-mediated base-pair formation was particularly suitable to modulate the aptamer function when the Im:Im mispairs (and hence the resulting metal-mediated base pairs) were located close to the ATP-binding pocket of the aptamer. Being able to trigger the aptamer function opens new possibilities for applications of oligonucleotides.

中文翻译：

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将金属介导的碱基对掺入ATP适体中-使用银（I）离子调节适体功能

首次将金属介导的碱基对用于调节适体对其靶标的亲和力。特别是，将两种人工咪唑2'-脱氧核糖核苷（Im）掺入已建立的ATP结合适体（ATP，三磷酸腺苷）的各个位置，导致形成三个带有Im：Im错配且ATP亲和力降低的适体衍生物。使用荧光光谱测定法和与固定的ATP的结合测定法来评估适体衍生物。每个错配添加一个Ag（I）离子后，就形成了稳定的Im–Ag（I）–Im碱基对。结果，适体衍生物对ATP的亲和力再次恢复。当Im：时，银（I）介导的碱基对形成特别适合于调节适体功能。Im错配（因此产生的金属介导的碱基对）位于适体的ATP结合口袋附近。能够触发适体功能为寡核苷酸的应用开辟了新的可能性。