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The role of Mg(2+) ion in flavin (flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN)) recognition by RNA aptamer has been explored through steady state and time-resolved fluorescence, circular dichroism (CD), thermal melting (TM) and isothermal titration calorimetry (ITC) studies. A strong quenching of flavin emission is detected due to stacking interaction with the nucleobases in the mismatched region of aptamer, and it enhances manifold with increasing Mg(2+) concentrations. A comparatively lower binding affinity toward FAD compared to FMN is attributed to the presence of intramolecular 'stack' conformer of FAD, which cannot participate in the intermolecular stacking interactions with the nucleobases. CD and TM studies predict that flavin detection causes structural reformation of RNA aptamer. ITC results indicate that flavin detection is thermodynamically feasible and highly enthalpy driven.
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http://dx.doi.org/10.1016/j.jphotobiol.2014.08.007 | DOI Listing |
Anal Chim Acta
November 2025
HIV-1 Molecular Epidemiology Laboratory, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Microbiology Department, Hospital Universitario Ramón y Cajal, CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, 28034, Spain. Electronic address:
Background: Currently, 39.9 million people are infected with the human immunodeficiency virus (HIV), and 1.3 million new infections occur annually, with over 170 circulating variants.
View Article and Find Full Text PDFAnal Chim Acta
November 2025
School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China; Anhui Provincial International Science and Technology Cooperation Base for Major Metabolic Diseases and Nutritional Interventions, Hefei, 230009, China; Intelligent Interconnected Systems Laboratory of A
Background: Copper is a vital trace element that plays a crucial role in various physiological processes due to its ability to exist in multiple oxidation states. Inspired by natural enzymes, researchers have developed copper-based nanozymes that mimic enzyme functions, offering cost-effective and stable alternatives to traditional enzymes. Despite their promising properties, the design and synthesis of these nanozymes can be complex and challenging.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, PR China. Electronic address:
Aptamers are single-stranded DNA or RNA oligonucleotides that can bind to specific target molecules with high affinity and specificity. Fluorescence DNA aptamer-based biosensors (aptasensors) have emerged as powerful analytical tools for detecting diverse targets, ranging from food contaminants to disease biomarkers, owing to their exceptional specificity, high sensitivity, and cost-effectiveness. This review systematically summarizes recent advances in the design strategies of fluorescence aptasensors, focusing on three key approaches: (1) fluorescence resonance energy transfer-based signal amplification, (2) nanomaterial-enhanced probes, and (3) multi-channel platforms for simultaneous detection.
View Article and Find Full Text PDFMikrochim Acta
September 2025
Henan Agricultural University, Zhengzhou, 450002, China.
A dual-mode aptasensor was engineered for aflatoxin B (AFB) detection by functional integration of peroxidase-mimetic Au@CeO core-shell nanostructures with emissive carbon dots (CDs). The Au@CeO nanocomposite, synthesized via spontaneous redox reaction, exhibited enhanced peroxidase-like activity due to abundant Ce/oxygen vacancies facilitating hydroxyl radical generation. The aptasensor utilizes a competitive binding mechanism, where AFB competed with immobilized Au@CeO-CDs-Apt1 probes for binding sites, resulting in inversely proportional colorimetric and fluorescent signals.
View Article and Find Full Text PDFThe SELEX process to identify RNA and DNA aptamers relies on sequencing selection rounds to detect highly specific aptamers through patterns of aptamer accumulation or enrichment. However, this approach infers rather than quantify aptamer specificity. Here we present a novel strategy for directly quantifying aptamer specificity within enriched libraries termed Aptamer Specificity Sequencing for Efficient Targeting (ASSET).
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