ANALYST
·
2020
·Vol. 145
·期 12
·4254-4259
·
IF 3.978
Qingqing Zhang,Tong Yang,Guoxiang Zheng,Heng Gao,Chenxiao Yan,Xiong Zheng,Xiaoshun Zhou,Yong Shao
G-triplex (G3) has been recognized as a popular intermediate during the folding of G-quadruplex (G4). This has raised interest to anticipate the ultimate formation of G3 by shortening the G4-forming oligonucleotides with the remaining three G-tracts. Some G3 structures have been validated and their stability has been found to be affected by the loop sequences similar to G4s. In this work, however, we first found that an intermolecular parallel G4 structure was preferred in K+ for the oligonucleotide 5′-TGGGTAGGGCGGG-3′ (DZ3) containing only three G-tracts. We screened auramine O (AO) as the appropriate fluorophore with a molecular rotor feature to target this G4 structure. AO bound with DZ3 in a 1 : 4 ratio, as confirmed by isothermal titration calorimetry experiments, suggesting the formation of a tetramolecular G4 structure (4erG4). The excimer emission from the labelled pyrene and the DNA melting behavior at various pHs in the presence of Ag+ proved the formation of the 4erG4 structure rather than the prevalent intramolecular G3 folding. This work demonstrates that one should be cautious while putatively predicting a G3 structure from an oligonucleotide containing three G-tracts.
研究领域:
生物化学
·
分子生物学
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DOI
PubMed
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 45
·28008-28013
·
IF 3.361
Congcong Gao,Baoquan Che,Hong Dai
EcoRI is an important biomacromolecule in live cells and protects bacterial cells against foreign DNA. In this work, we developed a simple and convenient G-triplex (G3) (5′-TGGGAAGGGAGGGAATTCCCT-3′)-based colorimetric assay for the rapid and selective detection of EcoRI activity and inhibition. The sequence specifically responds to EcoRI in the presence of K+ and hemin to form a G-triplex/hemin complex. Taking advantage of G-triplex, EcoRI activity was investigated under the optimized conditions. The absorption intensity ratio displayed a linear relationship against the concentration of EcoRI in the range 0 to 100 U mL−1, and the detection limit was 5.7 U mL−1. Furthermore, G3 showed good selectivity, and the ability to be used to screen for EcoRI inhibitors, indicating its potential in detection and analysis applications.
研究领域:
分子生物学
·
生物化学
·
分析化学
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DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2024
·
IF 5.7
Mengmeng Wu,Bing Yang,Lu Shi,Qiaorong Tang,Jing Wang,Wei Liu,Baoxin Li,Yan Jin
Background The human immunodeficiency virus (HIV) remains a major worldwide health problem. Nowadays, many methods have been developed for quantitative detecting human immunodeficiency virus DNA (HIV-DNA), such as fluorescence and colorimetry. However, these methods still have the disadvantages of being expensive and requiring professional technicians. Early diagnosis of pathogens is increasingly dependent on portable instruments and simple point-of-care testing (POCT). Therefore, it is meaningful and necessary to develop portable and cheap methods for detecting disease markers. Results In this work, a label-free chemiluminescence (CL) method was developed for detecting HIV-DNA via a handheld luminometer. To achieve label-free target detection, the CL catalyst, G-triplex-hemin DNAzyme (G3-hemin DNAzyme), was in-situ assembled in the presence of HIV-DNA. For improving sensitivity, HIV-DNA induced the cyclic strand displacement reaction (SDR), which can form three G3-hemin DNAzymes in one cycle. So, the chemiluminescence reaction between luminol and H 2 O 2 was highly effectively catalyzed, and the CL intensity was linearly related with the concentration of HIV-DNA in the range of 0.05–10 nM with a detection limit of 29.0 pM. Due to the high specificity of hairpin DNA, single-base mismatch can be discriminated, which ensured the specific detection of HIV-DNA. Significance In-situ formation of G3-hemin DNAzyme led to label-free and selective detection without complex synthesis and functionalization. Therefore, it offers a cheap, selective, sensitive and portable method for detecting disease-related genes, which is promising for POCT of clinical diagnosis in resource-limited settings.
研究领域:
生物医学
·
分子诊断
·
临床检验
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产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2023
·
IF 7.4
Mengmeng Wu,Bing Yang,Lu Shi,Qiaorong Tang,Jing Wang,Wei Liu,Baoxin Li,Yan Jin
Receptors are crucial to the analytical performance of sensor arrays. Different from the previous receptors in sensor arrays, herein, peroxidase-mimicking DNAzymes were innovatively used as receptors to develop a label-free chemiluminescence sensor array for discriminating various heavy metal ions in complex samples. The peroxidase-mimicking DNAzymes are composed of functional oligonucleotides and hemin, including G-triplex-hemin DNAzyme (G3-DNAzyme), G-quadruplex-hemin DNAzyme (G4-DNAzyme), and the dimer of G-quadruplex-hemin DNAzyme (dG4-DNAzyme). Circular dichroism (CD) spectroscopy demonstrated that different metal ions diversely affect the conformation of G-quadruplex and G-triplex, resulting in a change in the activity of peroxidase-mimicking DNAzyme. Thus, the unique fingerprints formed to easily discriminate seven kinds of heavy metal ions by principal component analysis (PCA) within 20 min. The discrimination of unknown metal ions in tap water further confirmed its ability for discriminating multiple heavy metal ions. Moreover, it will not bring water pollution due to the good biocompatibility of DNA. Therefore, it not only merely offers a label-free, rapid, environment-friendly, and cheap (1.49 $) sensor assay for discriminating metal ions but also comes up with an innovative way for developing sensor arrays.
研究领域:
生物化学
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环境科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 2
·1-8
·
IF 6.232
Li Ruiying,Liu Qiang,Jin Yan,Li Baoxin
The authors have incidentally found that the three tandem repeats of a 13-mer G-rich oligomer (with sequence 5′-TGG GAA GGG AGG G-3′; referred to as G3) can directly fold into a stable G3 trimer. The G3 trimer/hemin DNAzyme exhibits an about 3-fold higher peroxidase-mimicking activity compared to the conventional G3/hemin DNAzyme. Combining this finding with rolling circle amplification (RCA), a colorimetric assay was developed for sensitive and specific determination of microRNA. In this method, each cycle of RCA generates three catalytic units. This leads to a significant signal amplification of the RCA. Using let-7a as a model analyte, the colorimetric method (best performed at 420 nm) exhibits high sensitivity toward microRNA-let-7a with a 37 fM detection limit and an analytical range that covers 3 orders of magnitude. The method was applied to the determination of let-7a in some cell lysates.
This G-triplex trimer-based rolling circle amplification (RCA) method can produce three catalytic units per RCA cycle, which can significantly improve the amplification efficiency of RCA.
研究领域:
生物化学
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分子生物学
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纳米技术
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分析化学
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产品关联
DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2021
·
IF 6.558
Fangming Chen,Xingchuang Fu,Yao Meng,Mingrui Jiang,Jian Wang,Ying-Lin Zhou,De-Wen Zhang
A miniaturized platform combining integrated microelectrode (IME) and functional nucleic acids was developed for homogeneous label-free electrochemical biosensing. IME was constructed with a carbon fiber microelectrode and a platinum wire in a θ type glass tube as a two-electrode system for electrochemical monitoring at microliter level. A newly reported G-triplex/methylene blue (G3/MB) complex was used as the signal generator in the homogeneous label-free electrochemical biosensor . G3 has strong affinity with MB and it can cause significant decrease of the diffusion current of MB after binding. Melamine was chosen as the model target. Since melamine can interact with nucleobase thymine (T) to form T-melamine-T structure through complementary hydrogen bonds , a single-strand functional DNA hairpin structure with poly T and G3 elaborately blocked via base pairing was designed. The presence of melamine can trigger the conformation switching of the DNA hairpin to release the G3. The released G3 combined with MB could therefore change the diffusion current, leading to a simple and rapid detection of melamine. The combination of functional DNA hairpin as target recognition element, G3/MB as signal generator, and IME as transducer provided a “Mix and Measure” miniaturized platform for the construction of homogeneous label-free electrochemical biosensors.
研究领域:
电化学
·
生物传感器
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分析化学
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核酸化学
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DOI
PubMed
高影响因子
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