The molecular mechanisms of P-glycoprotein (P-gp; also known as MDR1 or ABCB1) have been mainly investigated using artificial membranes such as lipid-detergent mixed micelles, artificial lipid bilayers, and membrane vesicles derived from cultured cells. Although these experiments help illustrate details about the molecular mechanisms of P-gp, they do not reflect physiological membrane environments in terms of lateral pressure, curvature, constituent lipid species, The protocol presented here includes a detailed guide for analyzing the conformational change of human P-gp in living HEK293 cells by using intramolecular fluorescence resonance energy transfer (FRET), in which excitation of the donor fluorophore is transferred to the acceptor without emission of a photon when two fluorescent proteins are in close proximity. Combining FRET analysis with membrane permeabilization, the contribution of small molecules such as nucleotides to the conformational change can be evaluated in living cells.
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http://dx.doi.org/10.21769/BioProtoc.3930 | DOI Listing |
Brain
January 2025
Institute of Neurological Sciences and Psychiatry, Hacettepe University, 06100, Ankara, Turkey.
Cortical spreading depolarization (CSD), the neurophysiological event believed to underlie aura, may trigger migraine headaches through inflammatory signaling that originates in neurons and spreads to the meninges via astrocytes. Increasing evidence from studies on rodents and migraine patients supports this hypothesis. The transition from pro-inflammatory to anti-inflammatory mechanisms is crucial for resolving inflammation.
View Article and Find Full Text PDFSci Rep
January 2025
Molecular Modeling and Simulation Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 4-9-1, Anagawa, Inage-Ku, Chiba City, Chiba, 263-8555, Japan.
Sequence-dependent mechanical properties of DNA could play essential roles in nuclear processes by affecting histone-DNA interactions. Previously, we found that the DNA entry site of the first nucleosomes from the transcription start site (+ 1 nucleosome) in budding yeast enriches AA/TT steps, but not the exit site, and the biased presence of AA/TT in the entry site was associated with the transcription levels of yeast genes. Because AA/TT is a rigid dinucleotide step, we considered that AA/TT causes DNA unwrapping.
View Article and Find Full Text PDFBiomed Opt Express
January 2025
School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China.
Accurate and efficient determination of malachite green (MG) in aquaculture is crucial for ensuring environment and food safety. Herein, we present a dual-response fluorescence probe based on an Ag/PMMA/Eu nanocomposite for the sensitive detection of MG with low concentration and single droplet. The luminescence properties of the Ag/PMMA/Eu nanocomposite and the fluorescence resonance energy transfer (FRET) effect between Eu and MG are significantly improved due to the localized surface plasmon resonance (LSPR) effect.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
A sensitized dual-response ratiometric fluorescent sensor integrated smartphone platform for accurate discrimination and detection of tetracycline (TC) homologues was fabricated based on N-CDs-Eu complex. In the sensing system, N-CDs act as a sensitizer of Eu and significantly enhance the fluorescence of TC-Eu complex approximate 40-fold owing to the synergistic effect of antenna effect (AE) and fluorescence resonance energy transfer (FRET). A paper sensor integrated with a smartphone platform is further fabricated for on-site measurement of TC.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Single Molecule Analysis Group, Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109, United States.
Single-molecule fluorescence resonance energy transfer (smFRET) has emerged as a pivotal technique for probing biomolecular dynamics over time at nanometer scales. Quantitative analyses of smFRET time traces remain challenging due to confounding factors such as low signal-to-noise ratios, photophysical effects such as bleaching and blinking, and the complexity of modeling the underlying biomolecular states and kinetics. The dynamic distance information shaping the smFRET trace powerfully uncovers even transient conformational changes in single biomolecules both at or far from equilibrium, relying on trace idealization to identify specific interconverting states.
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