BIOMACROMOLECULES
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2022
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IF 6.978
Hao Sun,Haifeng Wu,Qiao Teng,Yuanxi Liu,Hui Wang,Zhen-Gang Wang
In enzymatic active sites, the essential functional groups are spatially arranged as a result of the enzyme three-dimensional folding, which leads to remarkable catalytic properties. We are inspired to self-assemble the polylysine peptides with guanine-rich DNA and hemin as cofactor to fabricate the peroxidase-mimicking catalytic nanomaterials. The DNA can fold into G-quadruplex to provide a supramolecular scaffold and a nucleobase for supporting and coordinating hemin, and the polylysine provides amine as distal groups to promote the H2O2 adsorption to the iron of hemin. The polylysine and DNA components synergistically accelerated the hemin-catalyzed reactions, and the complex containing ε-polylysine exhibited higher activity than α-polylysine. This activity difference is attributed to the higher pKa value and more susceptible protonation of amine of ε-polylysine than α-polylysine. The ε-polylysine/DNA/hemin had similar coordination states of hemin and conformations of the components to α-polylysine/DNA/hemin but accelerated the formation of the intermediate compound I faster than α-polylysine. Theoretical simulation reveals that the unprotonated NH2 behaved like a base catalyst, similar to His-42 residue in the natural heme pocket, while the protonated NH3+ acted as an acid, which indicated that the base catalyst on the distal side of the hemin pocket is more active than the acid. This work provides an avenue to control the distribution of the catalytic residues in an enzyme-like active site and to understand the roles of the key residues of native enzymes.
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高影响因子
MICROCHEMICAL JOURNAL
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2026
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IF 5.2
Lingsong Lu,Bei Liu
3D porous Fe 3 O 4 @ZIF-90 interface provides high-density DNA loading sites. • Mn 2+ -gated DNAzyme walker ensures a low-background controllable assay. • DNAzyme walker and CRISPR-Cas13a cascade enable dual signal amplification. • The biosensor demonstrated high accuracy and specificity in human serum samples. The precise quantification of Mucin-1 (MUC1) is vital for the early diagnosis and therapeutic monitoring of epithelial malignancies. In this study, a fluorescent biosensing platform based on a 3D porous metal-organic framework (MOF) and a cascaded signal amplification strategy was developed for MUC1 detection, driven by a target-induced conformational switch and Mn 2+ -dependent catalytic DNAzyme walking. Porous Fe 3 O 4 @ZIF-90 nanocomposites were used to construct the sensing interface, which co-immobilized dormant DNAzyme/aptamer duplexes and a high-density layer of substrate DNA (sub-DNA), serving as a robust platform for the subsequent walking process. Upon specific MUC1 recognition, the aptamer preferentially captures the target MUC1. The thermodynamic driving force induces the dissociation of the MUC1/aptamer complex, liberating the DNAzyme engine. Following magnetic separation to eliminate matrix interferences, the addition of Mn 2+ triggers the processive inter-molecular migration of the DNAzyme walker across the sub-DNA immobilized 3D porous Fe 3 O 4 @ZIF-90 interface via successive hybridization and site-specific cleavage of internal riboadenosine (rA) junctions. This inter-molecular walking process generates a high flux of trigger strands, which subsequently activates the CRISPR-Cas13a system for a robust trans -cleavage of dual-labeled fluorophore-quencher (FQ) reporters. The resulting degradation of FQ reporter enables sensitive MUC1 quantification through exponential fluorescence recovery. By synergizing the structure advantages of the 3D MOF with this cascaded signal amplification, the biosensor achieved a wide linear range from 0.37 nM to 500 nM with a low detection limit of 17.2 pM. Furthermore, the biosensor exhibited reliable specificity and recovery (102.28%–106.94%) in complex human serum assays. The proposed strategy effectively minimizes non-specific background leakage, demonstrating promising potential for the ultra-sensitive detection of MUC1 in complex biological matrices. Schematic presentation of the fluorescent biosensor for the determination of Mucin-1 based on a 3D porous Fe 3 O 4 @ZIF-90 interface and DNAzyme walker-mediated CRISPR-Cas13a cascade. Download: Download high-res image (117KB) Download: Download full-size image
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MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Ruimin Li,Yilin Gong,Shuibin Cen,Xueguo Song,Hua Xiang,Runkun Zhang
A novel dual-color method for glucose detection has been devised, leveraging the combination of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium (ABTS 2− ) and acid violet 7, based on the catalytic properties of G-quadruplex DNAzymes. In the presence of K + , the oligonucleotide 5′-GTGGGTAGGGCGGGTTGG-3′ (PS2.M) forms a G-quadruplex structure. When bound to hemin, this structure mimics horseradish peroxidase (HRP) and catalyzes the oxidation of colorless ABTS 2− to green ABTS •− by H 2 O 2 . The H 2 O 2 is produced through the reaction between glucose and oxygen, catalyzed by glucose oxidase. By linking these two reactions, the oxidation of glucose can be translated into a color change in ABTS 2− . Under optimal conditions, the absorbance at 420 nm (A 420 nm ) is directly proportional to the glucose concentration within a range of 1.0 μM to 40.0 μM. The linear regression equation is A = 0.175 + 0.0334C (C: μM, R = 0.998), with a detection limit of 0.1 μM (3σ/slope). Furthermore, the introduction of acid violet 7 as a reference molecule enables the green color intensity change to be transduced into a color transition from red to gray and then to green, facilitating high-resolution semi-quantitative analysis of glucose by visual inspection. Importantly, our proposed method has been validated through its application to the detection of glucose concentrations in human serum, yielding promising results that underscore its potential for clinical diagnostics and research applications. Our findings represent a substantial advancement in the field of glucose detection and offer a promising alternative to existing methods.
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Scientific Reports
·
2018
·Vol. 8
·期 1
·1-8
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IF 4.122
Zhang Hong,Li Xintong,He Fan,Zhao Mingqin,Ling Liansheng
A novel turn-off colorimetric sensor for sequence-specific recognition of single-stranded DNA (ssDNA) was established by combining Y-shaped DNA duplex and G-quadruplex-hemin DNAzyme. A G-rich single-stranded DNA (Oligo-1) displays peroxidase mimicking catalytic activity due to the specific binding with hemin in the presence of K + , which was able to catalyze the oxidation of colorless 2,2′-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS 2− ) by H 2 O 2 to generate green ABTS− radical for colorimetric assay. Oligonucleotide 2 (Oligo-2) was partly complementary with Oligo-1 and the target DNA. Upon addition of target DNA, Oligo-1, Oligo-2 and target DNA can hybridize with each other to form Y-shaped DNA duplex. The DNAzyme sequence of Oligo-1 was partly caged into Y-shaped DNA duplex, resulting in the inactivation of the DNAzyme and a sharp decrease of the absorbance of the oxidation product of ABTS 2− . Under the optimum condition, the absorbance decreased linearly with the concentration of target DNA over the range of 1.0–250 nM and the detection limit was 0.95 nM (3σ/slope) Moreover, satisfied result was obtained for the discrimination of single-base or two-base mismatched DNA.
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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高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 7
·1-8
·
IF 5.479
Zhou Jiao,Ling Yu,Li Nian Bing,Luo Hong Qun
The authors describe a fluorometric and resonance Rayleigh scattering dual-mode scheme for detection of the activity and inhibition of alkaline phosphatase (ALP). The method utilizes (a) CoOOH nanoflakes, which have high resonance Rayleigh scattering activity and can strongly adsorb ssDNA, and (b) Co(II)-dependent DNAzyme assisted signal amplification. ALP specifically catalyzes the hydrolysis of ascorbic acid-2-phosphate to produce ascorbic acid which reduces CoOOH nanoflakes to Co(II) ion. The Co(II)-dependent DNAzyme is then activated by Co(II) ion, and this results in the cleavage of a substrate labeled with both a fluorophore and a quencher. Following hydrolysis, fluorophore and quencher become separated and the fluorescence measured at excitation/emission wavelengths of 490/518 nm recovers, while the RRS signal at 405 nm decreases. The method works on the 0.2 to 2000 U L −1 ALP activity range, and the detection limit is 0.05 U L −1 . The method was used to validate the mechanism of the action of two classical ALP inhibitors (EDTA and Na 3 VO 4 ). Conceivably, it can also be applied to screen for ALP inhibitors.
A bioprobe composed of cobalt oxyhydroxide (CoOOH) nanoflakes as the substrate and carrier, and Co 2+ -dependent DNAzyme containing guanine ribonucleotide (rG) and uracil ribonucleotide (rU) for circularly signal amplification is used for fluorometric determination of alkaline phosphatase (ALP) activity.
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高影响因子
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