State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Hunan University, Changsha 410082, China.
Anal Chem. 2024 Nov 12;96(45):18079-18085. doi: 10.1021/acs.analchem.4c03934. Epub 2024 Oct 30.
Allostery is a phenomenon where the binding of a ligand at one allosteric site influences the affinity for another ligand at an active site. Different from orthosteric regulation, it allows for more precise control of biomolecular activity and enhances the stability of the molecules. Inspired by allosteric regulation of natural molecules, we present a Y-shaped allosteric DNA nanodevice, termed YssAP, that was pH-responsive and functionalized with the AS1411 aptamer for accurate fluorescence imaging of human apurinic/apyrimidinic endonuclease (APE1) activity in tumor cells. With rational design, YssAP could not be cut by APE1, and Cy5 was in the proximity of BHQ2, leading to suppressed signal emission. In contrast, since acidic pH acted as an allosteric effector, YssAP underwent a conformational change into an activated DNA probe (YdsAP) at acidic extracellular pH. After entering the tumor cell via the specific recognition of AS1411 aptamer, the overexpressed APE1 in the tumor cell cut the AP site on YdsAP. Cy5 moved far away from BHQ2, resulting in a strong signal output. Compared with the direct construction of the APE1 substrate, allosteric DNA nanodevices have more accurate imaging effects, which can be precisely adjusted by changing the switching state. We anticipate that this strategy will be applied in the screening of APE1 inhibitors and precise tumor diagnosis.
变构作用是一种现象，即配体在一个变构位点的结合会影响其在活性位点与另一个配体的亲和力。与变构调节不同，它可以实现对生物分子活性的更精确控制，并增强分子的稳定性。受天然分子变构调节的启发，我们提出了一种 Y 型变构 DNA 纳米器件，称为 YssAP，它对 pH 具有响应性，并具有 AS1411 适体的功能，可用于准确荧光成像肿瘤细胞中的人脱嘌呤/脱嘧啶内切酶 (APE1) 活性。通过合理的设计，YssAP 不能被 APE1 切割，并且 Cy5 靠近 BHQ2，导致信号发射受到抑制。相比之下，由于酸性 pH 作为变构效应物，YssAP 在酸性细胞外 pH 下转变为激活的 DNA 探针 (YdsAP)。通过 AS1411 适体的特异性识别进入肿瘤细胞后，肿瘤细胞中过表达的 APE1 切割 YdsAP 上的 AP 位点。Cy5 远离 BHQ2，导致信号输出强烈。与直接构建 APE1 底物相比，变构 DNA 纳米器件具有更准确的成像效果，可以通过改变开关状态进行精确调整。我们预计这种策略将应用于 APE1 抑制剂的筛选和精确的肿瘤诊断。
