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Forster resonance energy transfer

Chun-Yu Lin, Hsin-Yu Chang, Te-Fu Yeh, Hsisheng Teng, Shean-Jen Chen
The two-photon crosslinking of graphene oxide-quantum dots (GOQDs) adopts rose Bengal as the photoactivator to induce the GOQD assembly process. Based on the Förster resonance energy transfer mechanism with oxygen as the crosslinking medium, three-dimensional patterned GOQD microstructures with near diffraction-limit spatial resolution have been fabricated and analyzed by a multiphoton excited fabrication instrument/microscope.
December 1, 2017: Optics Letters
Adi Halle-Bikovski, Sophia Fried, Eva Rozentur-Shkop, Guy Biber, Hadassa Shaked, Noah Joseph, Mira Barda-Saad, Jordan H Chill
Wiskott-Aldrich syndrome protein (WASp) is exclusively expressed in hematopoietic cells and responsible for actin-dependent processes, including cellular activation, migration, and invasiveness. The C-terminal domain of WASp-Interacting Protein (WIP) binds to WASp and regulates its activity by shielding it from degradation in a phosphorylation dependent manner as we previously demonstrated. Mutations in the WAS-encoding gene lead to the primary immunodeficiencies Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT)...
December 7, 2017: ACS Chemical Biology
Markus Schneider, Kirsten Prudic, Anja Pippel, Manuela Klapperstück, Ursula Braam, Christa E Müller, Günther Schmalzing, Fritz Markwardt
P2X4 and P2X7 are members of the P2X receptor family, comprising seven isoforms (P2X1-P2X7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular ATP. P2X4 and P2X7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. Although functional heteromerization has been established for P2X2 and P2X3 subunits expressed in sensory neurons, there are contradictory reports regarding a functional interaction between P2X4 and P2X7 subunits...
2017: Frontiers in Pharmacology
Amicia D Elliott, Noah Bedard, Alessandro Ustione, Michelle A Baird, Michael W Davidson, Tomasz Tkaczyk, David W Piston
Fluorescent protein (FP) biosensors based on Förster resonance energy transfer (FRET) are commonly used to study molecular processes in living cells. There are FP-FRET biosensors for many cellular molecules, but it remains difficult to perform simultaneous measurements of multiple biosensors. The overlapping emission spectra of the commonly used FPs, including CFP/YFP and GFP/RFP make dual FRET measurements challenging. In addition, a snapshot imaging modality is required for simultaneous imaging. The Image Mapping Spectrometer (IMS) is a snapshot hyperspectral imaging system that collects high resolution spectral data and can be used to overcome these challenges...
2017: PloS One
Natalia Rizeq, Savvas N Georgiades
Oligomeric compounds, constituted of consecutive N,O-heteroaromatic rings, introduce useful and tunable properties as alternative ligands for biomolecular recognition. In this study, we have explored a synthetic scheme relying on Van Leusen oxazole formation, in conjunction with C-H activation of the formed oxazoles and their subsequent C-C cross-coupling to 2-bromopyridines in order to assemble a library of variable-length, 'head-to-tail'-connected, pyridyl-oxazole ligands. Through investigation of the interaction of the three longer ligands (5-mer, 6-mer, 7-mer) with cancer-relevant G-quadruplex structures (human telomeric/22AG and c-Myc oncogene promoter/Myc2345-Pu22), the asymmetric pyridyl-oxazole motif has been demonstrated to be a prominent recognition element for G-quadruplexes...
December 6, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Xing Guo, Lin Wang, Kayla Duval, Jing Fan, Shaobing Zhou, Zi Chen
Trans-activating transcriptional activator (TAT), a cell-penetrating peptide, is extensively used for facilitating cellular uptake and nuclear targeting of drug delivery systems. However, the positively charged TAT peptide strongly interacts with serum components and undergoes substantial phagocytosis by the reticuloendothelial system, causing a short blood circulation in vivo. In this work, an acid-active tumor targeting nanoplatform DA-TAT-PECL is developed to inhibit the nonspecific interactions of TAT in the bloodstream...
December 6, 2017: Advanced Materials
Alexander Orenstein, April S Berlyoung, Elizabeth E Rastede, Ha H Pham, Elise Fouquerel, Connor T Murphy, Brian J Leibowitz, Jian Yu, Tumul Srivastava, Bruce A Armitage, Patricia L Opresko
Measurement of telomere length by fluorescent in situ hybridization is widely used for biomedical and epidemiological research, but there has been relatively little development of the technology in the 20 years since it was first reported. This report describes the use of dual gammaPNA (γPNA) probes that hybridize at alternating sites along a telomere and give rise to Förster resonance energy transfer (FRET) signals. Bright staining of telomeres is observed in nuclei, chromosome spreads and tissue samples...
December 2, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Veerle Van Meervelt, Misha Soskine, Shubham Singh, Gea Schuurman-Wolters, Hein J Wijma, Bert Poolman, Giovanni Maglia
Protein conformations play crucial roles in most, if not all, biological processes. Here we show that the current carried through a nanopore by ions allows monitoring conformational changes of native substrate-binding domains (SBD) of an ATP-Binding Cassette importer in real-time. Comparison with single-molecule Förster Resonance Energy Transfer (smFRET) and ensemble measurements revealed that proteins trapped inside the nanopore have bulk-like properties. Two ligand-free and two ligand-bound conformations of SBD proteins were inferred and their kinetic constants were determined...
December 5, 2017: Journal of the American Chemical Society
Jeroen Sol, Volker Dehm, Reinhard Hecht, Frank Würthner, Albertus Schenning, Michael Debije
Temperature-responsive luminescent solar concentrators (LSCs) have been fabricated in which the Förster resonance energy transfer (FRET) between a donor-acceptor pair in a liquid crystalline solvent can be tuned. At room temperatures, the perylene bisimide (PBI) acceptor is aggregated and FRET is inactive, while after heating to above the isotropic phase of the liquid crystal solvent, the acceptor PBI completely dissolves and FRET is activated. This unusual temperature control over FRET was used to design a color-tunable LSC...
December 4, 2017: Angewandte Chemie
Dan Wu, Yang Li, Jie Yang, Jie Shen, Jiong Zhou, Qinglian Hu, Guocan Yu, Guping Tang, Xiaoyuan Chen
An amphiphilic supramolecular brush copolymer CB[8](PEG-Np·PTPE) was constructed on the basis of a novel host-guest molecular recognition model formed by cucurbit[8]uril (CB[8]), 4,4'-bipyridinium derivative (PQ) and PEGylated naphthol (PEG-Np). In aqueous solution, the resultant supramolecular brush copolymer self-assembled into supramolecular nanoparticles (SNPs), by which anticancer drug doxorubicin (DOX) was encapsulated in the hydrophobic core, establishing an artful Förster resonance energy transfer (FRET) system with dual-fluorescence quenched...
December 5, 2017: ACS Applied Materials & Interfaces
Piotr Grabarczyk, Passorn Winkler, Martin Delin, Praveen K Sappa, Sander Bekeschus, Petra Hildebrandt, Grzegorz K Przybylski, Uwe Völker, Elke Hammer, Christian A Schmidt
The BCL11B gene encodes a Krüppel-like, sequence-specific zinc finger transcription factor that acts as either a repressor or an activator, depending on its post-translational modifications. The importance of BCL11B in numerous biological processes in multiple organs has been well established in mouse knockout models. The phenotype of the first de novo monoallelic germline missense mutation in the BCL11B gene (N441K) strongly implies that the mutant protein acts in a dominant negative manner by neutralizing the unaffected protein through the formation of a nonfunctional dimer...
December 4, 2017: Molecular and Cellular Biology
Masanao Kinoshita, Hikaru Ano, Michio Murata, Kenta Shigetomi, Junichi Ikenouchi, Nobuaki Matsumori
Imaging the distribution of sphingomyelin (SM) in membranes is an important issue in lipid-raft research. Recently we developed novel fluorescent SM analogs that exhibit partition and dynamic behaviors similar to native SM, and succeeded in visualizing lateral domain-segregation between SM-rich liquid-ordered (Lo) and SM-poor liquid-disordered (Ld) domains. However, because the fluorescent contrast between these two domains depends directly on their partition ratio for the fluorescent SMs, domain-separation becomes indeterminate when the distribution difference is not great enough...
December 1, 2017: Scientific Reports
Priya Singh, Susobhan Choudhury, Senthilguru Kulanthaivel, Damayanti Bagchi, Indranil Banerjee, Saleh A Ahmed, Samir Kumar Pal
The efficacy and toxicity of drugs depend not only on their potency but also on their ability to reach the target sites in preference to non-target sites. In this regards destabilization of delivery vehicles induced by light can be an effective strategy for enhancing drug delivery with spatial and temporal control. Herein we demonstrate that the photoinduced isomerization from closed (hydrophobic) to open isomeric form (hydrophilic) of a novel DHI encapsulated in liposome leads to potential light-controlled drug delivery vehicles...
November 15, 2017: Colloids and Surfaces. B, Biointerfaces
Fanny Cayre, Simona Mura, Bohdan Andreiuk, Dunja Sobot, Sandrine Gouazou, Didier Desmaële, Andrey S Klymchenko, Patrick Couvreur
Förster resonance energy transfer (FRET) is used here for the first time to monitor the in vivo fate of nanoparticles made of the squalene-gemcitabine prodrug and two novel derivatives of squalene with the cyanine dyes 5.5 and 7.5, which behave as efficient FRET pair in the NIR region. Following intravenous administration, nanoparticles initially accumulate in the liver, then they show loss of their integrity within 2 h and clearance of the squalene bioconjugates is observed within 24 h. Such awareness is a key prerequisite before introduction into clinical settings...
November 30, 2017: Advanced Healthcare Materials
Ajmeeta Sangtani, Eleonora Petryayeva, Miao Wu, Kimihiro Susumu, Eunkeu Oh, Alan L Huston, Guillermo Lasarte-Aragones, Igor L Medintz, W Russ Algar, James B Delehanty
Nanoparticle (NP)-mediated drug delivery (NMDD) has emerged as a novel method to overcome the limitations of traditional systemic delivery of therapeutics, including the controlled release of the NP-associated drug cargo. Currently, our most advanced understanding of how to control NP-associated cargos is in the context of soft nanoparticles (e.g., liposomes), but less is known about controlling the release of cargos from the surface of hard NPs (e.g., gold NPs). Here we employ a semiconductor quantum dot (QD) as a prototypical hard NP platform and use intracellularly- triggered actuation to achieve spatiotemporal control of drug release and modulation of drug efficacy...
November 30, 2017: Bioconjugate Chemistry
Ekaterina Sobakinskaya, Marcel Schmidt Am Busch, Thomas Renger
Förster resonance energy transfer (FRET) is an important mechanism for the estimation of intermolecular distances, e.g., in fluorescent labelled proteins. The interpretations of FRET experiments with standard Förster theory relies on the following approximations: (i) a point-dipole approximation (PDA) for the coupling between transition densities of the chromophores, (ii) a screening of this coupling by the inverse optical dielectric constant of the medium, and (iii) the assumption of a fast isotropic sampling over the mutual orientations of the chromophores...
November 30, 2017: Journal of Physical Chemistry. B
Naoto Yoshinaga, Takehiko Ishii, Mitsuru Naito, Taisuke Endo, Satoshi Uchida, Horacio Cabral, Kensuke Osada, Kazunori Kataoka
Polyplexes as gene delivery carriers require integrated functionalities to modulate intracellular trafficking for efficient gene transfection. Herein, we developed plasmid DNA (pDNA)-loaded polyplex micelles (PMs) from poly(ethylene glycol) (PEG)-based block catiomers derivatized with 4-carboxy-3-fluorophenylboronic acid (FPBA) and D-gluconamide (GlcAm) to form pH- and ATP-responsive crosslinking in the core. These PMs exhibited robustness in the extracellular milieu, smooth endosomal escape after cellular uptake, and facilitated pDNA decondensation triggered by increased ATP concentration inside of the cell...
November 30, 2017: Journal of the American Chemical Society
Haruna Takeda, Etsuko Kiyokawa
Intestinal epithelial cells function as a barrier to protect our body from various agents; therefore, any damage to these cells must be immediately repaired. Several in vivo and vitro studies have shown the involvement of Erk (extracellular signal-regulated kinase) in the regeneration process; however, the spatial regulation of Erk related to tissue morphology has not been well documented. Using two-photon microscopy and mice carrying a Förster resonance energy transfer-based biosensor, we here monitored the Erk activity in the ileal epithelial cells of living mice...
November 28, 2017: Scientific Reports
Mariko Yamaguchi, Emi Ohta, Takuya Muto, Takayoshi Watanabe, Takahiro Hohsaka, Yoichi Yamazaki, Hironari Kamikubo, Mikio Kataoka
Structural characterization of fully unfolded proteins is essential for understanding not only protein-folding mechanisms, but also the structures of intrinsically disordered proteins. Because an unfolded protein can assume all possible conformations, statistical descriptions of its structure are most appropriate. For this purpose, we applied Förster resonance energy transfer (FRET) analysis to fully unfolded staphylococcal nuclease. Artificial amino acids labeled with a FRET donor or acceptor were introduced by an amber codon and a four-base codon respectively...
November 25, 2017: Biophysical Reviews
Diego Duchi, Kristofer Gryte, Nicole C Robb, Zakia Morichaud, Carol Sheppard, Konstantin Brodolin, Sivaramesh Wigneshweraraj, Achillefs N Kapanidis
Transcription initiation is a major step in gene regulation for all organisms. In bacteria, the promoter DNA is first recognized by RNA polymerase (RNAP) to yield an initial closed complex. This complex subsequently undergoes conformational changes resulting in DNA strand separation to form a transcription bubble and an RNAP-promoter open complex; however, the series and sequence of conformational changes, and the factors that influence them are unclear. To address the conformational landscape and transitions in transcription initiation, we applied single-molecule Förster resonance energy transfer (smFRET) on immobilized Escherichia coli transcription open complexes...
November 21, 2017: Nucleic Acids Research
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