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Unlocking Pb2+ Sensing Potential in a DNA G-Quadruplex via Loop Modification with Fluorescent Chalcone Surrogates
ACS Sensors ( IF 8.2 ) Pub Date : 2023-12-08 , DOI: 10.1021/acssensors.3c01866
Ryan E Johnson 1 , Makay T Murray 2 , Dylan J Roby 1 , Lucas J Bycraft 1 , Zachary R Churcher 3 , Saanya Yadav 2 , Philip E Johnson 3 , Stacey D Wetmore 2 , Richard A Manderville 1
Affiliation  

The ability of guanine (G)-rich DNA to bind toxic lead (Pb2+) ions within a G-quadruplex (GQ) motif is a leading DNA biosensor strategy. A major analytical hurdle for GQ detection of Pb2+ is competitive GQ templating by potassium (K+) ions. We employ the on-strand DNA synthesis of internal fluorescent chalcone surrogates within the 15-mer thrombin binding aptamer (TBA15) to address this challenge. Replacement of thymidine at the 3-position (T3) within TBA15 with an indole-4-hydroxy-indanone (Ind4HI) chalcone strongly decreases K+-GQ stability while enhancing Pb2+-GQ stability to increase Pb2+ binding specificity. The new T3-Ind4HI probe exhibits a 15-fold increase in fluorescence intensity upon binding of Pb2+ by the modified TBA15 and can detect 6.4 nM Pb2+ in the presence of 10 mM K+. Thus, replacement of the T3 residue of TBA15 with the new Ind4HI probe modulates metal ion affinity by native TBA15 to solve the analytical challenge posed by K+ in real water samples for detecting Pb2+ to meet regulatory guidelines by using a GQ biosensor.

中文翻译:


通过荧光查耳酮替代物的环修饰解锁 DNA G-四链体中的 Pb2+ 传感潜力



富含鸟嘌呤 (G) 的 DNA 能够在 G 四联体 (GQ) 基序内结合有毒铅 (Pb 2+ ) 离子,这是一种领先的 DNA 生物传感器策略。 GQ 检测 Pb 2+的一个主要分析障碍是钾 (K + ) 离子的竞争性 GQ 模板。我们采用 15 聚体凝血酶结合适体 (TBA15) 内内部荧光查尔酮替代物的链上 DNA 合成来应对这一挑战。用吲哚-4-羟基-茚满酮 (Ind4HI) 查耳酮替换 TBA15 中 3 位 (T3) 的胸苷会强烈降低 K + -GQ 稳定性,同时增强 Pb 2+ -GQ 稳定性以增加 Pb 2+结合特异性。新型 T3-Ind4HI 探针通过修饰的 TBA15 与 Pb 2+结合后,荧光强度增加了 15 倍,并且可以在 10 mM K +存在的情况下检测 6.4 nM Pb 2+ 。因此,用新的 Ind4HI 探针替换 TBA15 的 T3 残基可调节天然 TBA15 的金属离子亲和力,以解决实际水样中 K +带来的分析挑战,用于检测 Pb 2+以满足使用 GQ 生物传感器的监管指南。
更新日期:2023-12-08
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