title: Magnetic nanoparticles-cooperated fluorescence sensor for sensitive and accurate detection of DNA methyltransferase activity coupled with exonuclease III-assisted target recycling.
abstract: A fluorescence magnetic biosensor for the DNA methyltransferase activity was developed based on the cooperative amplification by combining the magnetic nanoparticles synergistic exonuclease III (Exo III)-assisted circular exponential amplification and a supramolecular structure ZnPPIX/G-quadruplex. First, a duplex DNA probe, which was constructed by the hybridization of a quadruplex-forming oligomer with a molecular beacon, was assembled on the magnetic nanoparticles (MNPs) as a reporter. A hairpin probe (HP)-containing sequence of GATC was used as the methylation substrate of DNA adenine methyltransferase (DAM). Once HP was methylated by DAM, it could be recognized and cleaved by Dpn I, which allows the release of a single-stranded DNA. The DNA (tDNA1) then hybridizes to the MNP probe, which then triggers the exonuclease III-mediated target exponential recycling reaction. Simultaneously, numerous quadruplex forming oligomers are liberated and folded into the G-quadruplex-ZnPPIX complexes with the help of zinc(ii)-protoporphyrin IX(ZnPPIX) on the MNP surface to give a remarkable fluorescence response. In the developed sensor, a small amount of target DAM can be converted to a large number of stable DNA triggers, leading to remarkable amplification of the target. Moreover, using MNPs as a vector of the sensor may reduce the interference from the real samples, which increases the anti-interference of the sensing system. Based on this unique amplification strategy, a very low detection limit down to 2.0 × 10(-4) U mL(-1) was obtained. Furthermore, the sensor could be used to evaluate the DAM activity in different growth stages of E. coli cells and screen Dam MTase inhibitors. Therefore, the strategy proposed here provides a promising platform for monitoring the activity and inhibition of DNA MTases and has great potential to be applied further in early clinical diagnostics and medical research.
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Qingwang
authors.initials: Q
authors.lastname: Xue
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Youna
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Shuling
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Haibo
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Yuanfu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Yue
authors.affiliation: Shandong Provincial Key Lab of Test Technology on Food Quality and Safety, Shandong Academy of Agricultural Sciences, Jinan, 250100, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Gu
authors.affiliation: Shandong Provincial Key Lab of Test Technology on Food Quality and Safety, Shandong Academy of Agricultural Sciences, Jinan, 250100, China.
authors.forename: Shuqiu
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn and Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China.
authors.forename: Jifeng
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng, 252059, Shandong, China. liujifeng111@gmail.com hswang@lcu.edu.cn.
authors.forename: Huaisheng
authors.initials: H
authors.lastname: Wang
mesh_terms: D015254:DNA Modification Methylases / Q000032:analysis / Q000378:metabolism*; D057075:Enzyme Assays / Q000379:methods*; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000737:chemistry*; D054856:G-Quadruplexes; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D058185:Magnetite Nanoparticles; D015254:DNA Modification Methylases; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III