Changes in fluorescence emission intensity and anisotropy can reflect changes in the environment and molecular motion of a fluorophore. Researchers can capitalize on these characteristics to assess the affinity and specificity of DNA-binding proteins using fluorophore-labeled oligonucleotides. While there are many advantages to measuring binding using fluorescent oligonucleotides, there are also some distinct disadvantages. Here we describe some of the relevant issues for the novice, illustrating key points using data collected with a variety of labeled oligonucleotides and the relaxase domain of F plasmid TraI. Topics include selection of a fluorophore, experimental design using a fluorometer equipped with an automatic titrating unit, and analysis of direct binding and competition assays.
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http://dx.doi.org/10.1016/S0076-6879(08)03412-5 | DOI Listing |
Anal Bioanal Chem
December 2024
Nanobiotechnology for Diagnostics (Nb4D), Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, Barcelona, 08034, Spain.
The presence of antibiotic residues in cow's milk entails high risk for consumers, the dairy industry, and the environment. Therefore, the development of highly specific and sensitive screening tools for the rapid and cost-effective identification of traces of these compounds is urgently needed. A multiplexed screening platform utilizing DNA-directed immobilization (DDI) was developed aiming to detect three classes of antibiotic residues (fluoroquinolones, sulfonamides, and tylosin) prevalently found in milk.
View Article and Find Full Text PDFMikrochim Acta
August 2024
The State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing, 210023, China.
A novel "turn-on" aptasensor for kanamycin (Kana) detection based on a new Förster resonance energy transfer (FRET) pair is reported. A new organic small molecule was employed as a high-efficiency quencher for fluorophore. Based on specific interactions between ssDNA and the quencher, an ingenious and amplified strategy was designed.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Guangxi Key Laboratory of Environmental Processes and Remediation in Ecologically Fragile Regions, Guangxi Normal University, Guilin 541004, PR China; Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin 541004, PR China. Electronic address:
Ampicillin (AMP) is a β-lactam antibiotic that can inhibit bacterial wall synthesis. The overuse and misuse of AMP makes it micropollutant that commonly found in food and various environmental media. In this work, a fluorescence polarization sensor was designed to sensitive detection of trace ampicillin based on click chemistry, using graphene oxide (GO) as a fluorescence polarization (FP) signal enhancement element.
View Article and Find Full Text PDFJ Phys Chem B
July 2024
Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, Frankfurt 60438, Germany.
ACS Appl Mater Interfaces
April 2024
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, Shanghai Frontiers Science Center of Genome Editing and Cell Therapy, East China Normal University, 500 Dongchuan Road, Shanghai 200241, P. R. China.
In this work, we present an array-based chemical nose sensor that utilizes a set of ensemble-modified aptamer (EMAmer) probes to sense subtle physicochemical changes on the cell surface for cancer cell identification. The EMAmer probes are engineered by domain-selective incorporation of different types and/or copies of positively charged functional groups into DNA scaffolds, and their differential interactions with cancer cells can be transduced through competitive adsorption of fluorophore-labeled EMAmer probes loaded on MoS nanosheets. We demonstrate that this MoS-EMAmer-based sensor array enables rapid and effective discrimination among six types of cancer cells and their mixtures with a concentration of 10 cells within 60 min, achieving a 94.
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