title: New function of exonuclease and highly sensitive label-free colorimetric DNA detection.
abstract: 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 colorimetric 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 colorimetric 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.
authors.affiliation: College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, PR China; State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China. Electronic address: lihongbo112@163.com.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, PR China.
authors.forename: Suqin
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, PR China. Electronic address: wuzaisheng@163.com.
authors.forename: Zaisheng
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, PR China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China. Electronic address: rqyu@hnu.edu.cn.
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D001483:Base Sequence; D003124:Colorimetry / Q000295:instrumentation*; D004247:DNA / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D021881:DNA, Catalytic / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005092:Exonucleases / Q000737:chemistry*; D052138:Genes, Neoplasm / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000295:instrumentation*; D013194:Staining and Labeling; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000235:genetics*
chemical_list: D021881:DNA, Catalytic; D016159:Tumor Suppressor Protein p53; D004247:DNA; D005092:Exonucleases
keywords: Colorimetric detection; Label-free; Multifunctional probe; New function of exonuclease; p53 gene