New function of exonuclease and highly sensitive label-free colorimetric DNA detection
New function of exonuclease and highly sensitive label-free colorimetric DNA detection
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核酸外切酶新功能和高灵敏无标记比色DNA检测
DOI：
10.1016/j.bios.2015.10.037
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发表时间：
2016-03-15
影响因子：
12.6
通讯作者：
Yu, Ruqin
中科院分区：
文献类型：
--
作者：
Li, Hongbo;Wang, Suqin;Yu, Ruqin
Enzymatic manipulation and modulation of nucleic acids are a central part of cellular function, protection, and reproduction, while rapid and accurate detection of ultralow amount of nucleic acids remains a major challenge in molecular biology research and clinic diagnosis of genetic diseases. Herein, we reported that exonuclease III can degrade the G-quadruplex structure, indicating the new exonuclease's function. Basing on the function of exonuclease III, a novel G-quadruplex-hemin DNAzyme-based calorimetric detection of tumor suppressor gene p53 was successfully developed. Although only one oligonucleotide probe was involved, the sensing strategy could suppress the optical background and achieve an efficient G-quadruplex-hemin DNAzyme-based signal amplification. Specifically, a label-free functional nucleic acid probe (called THzyme probe) was designed via introducing target DNA probe-contained hairpin structure into G-quadruplex DNAzyme. Even if this probe can fold into G-quadruplex structure in the presence of hemin very different from the double-stranded DNA, it is easily degraded by exonuclease III. Thus, no change in UV-vis absorption intensity is detected in the absence of target DNA. However, the hybridization of target DNA can protect the integrity and catalytic activity of THzyme probe, producing the DNAzyme-amplified calorimetric signal. As a result, the p53 gene was able to be detected down to 1.0 pM (final concentration in the signal-generating solution: 50.0 fM) and mismatched target DNAs were easily distinguished. It is expected that this simple sensing methodology for DNA detection can find its utility in point-of-care applications. (C) 2015 Elsevier B.V. All rights reserved.
