Visualizing the Quadruplex: From Fluorescent Ligands to Light-Up Probes

2012 ◽  
pp. 111-177 ◽  
Author(s):  
Eric Largy ◽  
Anton Granzhan ◽  
Florian Hamon ◽  
Daniela Verga ◽  
Marie-Paule Teulade-Fichou
Keyword(s):  
Fluorescent Ligands

scholarly journals Iterative fractionation of recycling receptors from lysosomally destined ligands in an early sorting endosome.

1989 ◽  
Vol 109 (6) ◽  
pp. 3303-3314 ◽  
Author(s):  
K W Dunn ◽  
T E McGraw ◽  
F R Maxfield
Keyword(s):  
Digital Image Analysis ◽  
High Efficiency ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Recycling Endosomes ◽  
Double Label ◽  
Fluorescent Ligands ◽  
Endocytic Vesicles ◽  
Endocytic Compartments ◽  
Very High

To study the fusion and separation of endocytic compartments, we have used digital image analysis to quantify the accumulation of fluorescent ligands in endosomes during continuous endocytosis for periods of 1-20 min. Fluorescently labeled transferrin (Tf) and low density lipoproteins (LDL) were used as markers of recycling receptors and lysosomally directed ligands respectively. By measuring the intensity of individual endosomes, we found that the amount of LDL per endosome increases 30-40-fold between 1 and 10 min and then plateaus. In contrast, the amount of Tf per endosome reaches a steady state within 2 min at a level that is only three to four times that at 1 min. We used pulse-chase double label methods to demonstrate that Tf cycles through the compartment in which the LDL accumulates. When both Tf and LDL are added to cells simultaneously for 2 min, nearly all endosomes contain both labels. With 2-4 min further incubation in the absence of external ligands, LDL-containing compartments become depleted of Tf as Tf is directed to para-Golgi recycling endosomes. However, if Tf is added to the medium 2-4 min after a pulse with LDL, most of the LDL-containing endosomes become labeled with Tf. The data indicate that at least 30-40 endocytic vesicles containing both Tf and LDL fuse with an endosomal compartment over a period of 5-10 min. LDL accumulates within this compartment and Tf is simultaneously removed. Simple mathematical models suggest that this type of iterative fractionation can lead to very high efficiency sorting.

scholarly journals I-Motif/miniduplex hybrid structures bind benzothiazole dyes with unprecedented efficiencies: a generic light-up system for label-free DNA nanoassemblies and bioimaging

2020 ◽  
Vol 48 (4) ◽  
pp. 1681-1690 ◽  
Author(s):  
Lili Shi ◽  
Pai Peng ◽  
Jiao Zheng ◽  
Qiwei Wang ◽  
Zhijin Tian ◽  
...  
Keyword(s):  
Cellular Membrane ◽  
Dynamics Simulation ◽  
Hybrid Structures ◽  
High Signal ◽  
Label Free ◽  
Ph Change ◽  
Optimal Sequence ◽  
Free Dna ◽  
Fluorescence Bioimaging ◽  
Fluorescent Ligands

Abstract I-motif DNAs have been widely employed as robust modulating components to construct reconfigurable DNA nanodevices that function well in acidic cellular environments. However, they generally display poor interactivity with fluorescent ligands under these complex conditions, illustrating a major difficulty in utilizing i-motifs as the light-up system for label-free DNA nanoassemblies and bioimaging. Towards addressing this challenge, here we devise new types of i-motif/miniduplex hybrid structures that display an unprecedentedly high interactivity with commonly-used benzothiazole dyes (e.g. thioflavin T). A well-chosen tetranucleotide, whose optimal sequence depends on the used ligand, is appended to the 5′-terminals of diverse i-motifs and forms a minimal parallel duplex thereby creating a preferential site for binding ligands, verified by molecular dynamics simulation. In this way, the fluorescence of ligands can be dramatically enhanced by the i-motif/miniduplex hybrids under complex physiological conditions. This provides a generic light-up system with a high signal-to-background ratio for programmable DNA nanoassemblies, illustrated through utilizing it for a pH-driven framework nucleic acid nanodevice manipulated in acidic cellular membrane microenvironments. It enables label-free fluorescence bioimaging in response to extracellular pH change.

Thiol-Functionalized IGEPAL® Surfactants as Novel Fluorescent Ligands for the Silica Coating of Gold Nanoparticles

2015 ◽  
Vol 56 (4) ◽  
pp. 249-256 ◽  
Author(s):  
Helena Gavilán-Rubio ◽  
João Paulo Coelho ◽  
Guillermo González-Rubio ◽  
Gloria Tardajos ◽  
José Osío Barcina ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Silica Coating ◽  
Fluorescent Ligands

scholarly journals Novel and High Affinity Fluorescent Ligands for the Serotonin Transporter Based on (S)-Citalopram

2014 ◽  
Vol 5 (6) ◽  
pp. 696-699 ◽  
Author(s):  
Vivek Kumar ◽  
Troels Rahbek-Clemmensen ◽  
Christian B. Billesbølle ◽  
Trine Nygaard Jorgensen ◽  
Ulrik Gether ◽  
...  
Keyword(s):  
Serotonin Transporter ◽  
High Affinity ◽  
Fluorescent Ligands

Characterization of benzodiazepine receptors with fluorescent ligands

1990 ◽  
Vol 4 (11) ◽  
pp. 2934-2940 ◽  
Author(s):  
R. Tyler McCabe ◽  
Brian R. Gosta ◽  
Rachel L. Miller ◽  
R. Hratchia Havunjian ◽  
Kenner C. Rige ◽  
...  
Keyword(s):  
Benzodiazepine Receptors ◽  
Fluorescent Ligands

scholarly journals N-Terminal Tagging with GFP Enhances Selectivity of Agitoxin 2 to Kv1.3-Channel Binding Site

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 802
Author(s):  
Oksana V. Nekrasova ◽  
Alexandra L. Primak ◽  
Anastasia A. Ignatova ◽  
Valery N. Novoseletsky ◽  
Olga V. Geras’kina ◽  
...  
Keyword(s):  
Binding Site ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Hek293 Cells ◽  
Kv1.3 Channel ◽  
C Terminus ◽  
Peptide Toxins ◽  
Fluorescent Ligands ◽  
Voltage Gated Channels ◽  
Green Fluorescent

Recently developed fluorescent protein-scorpion toxin chimeras (FP-Tx) show blocking activities for potassium voltage-gated channels of Kv1 family and retain almost fully pharmacological profiles of the parental peptide toxins (Kuzmenkov et al., Sci Rep. 2016, 6, 33314). Here we report on N-terminally green fluorescent protein (GFP)-tagged agitoxin 2 (GFP-L2-AgTx2) with high affinity and selectivity for the binding site of Kv1.3 channel involved in the pathogenesis of various (primarily of autoimmune origin) diseases. The basis for this selectivity relates to N-terminal location of GFP, since transposition of GFP to the C-terminus of AgTx2 recovered specific interactions with the Kv1.1 and Kv1.6 binding sites. Competitive binding experiments revealed that the binding site of GFP-L2-AgTx2 overlaps that of charybdotoxin, kaliotoxin 1, and agitoxin 2, the known Kv1.3-channel pore blockers. GFP-L2-AgTx2 was demonstrated to be applicable as a fluorescent probe to search for Kv1.3 pore blockers among individual compounds and in complex mixtures, to measure blocker affinities, and to visualize Kv1.3 distribution at the plasma membrane of Kv1.3-expressing HEK293 cells. Our studies show that definite combinations of fluorescent proteins and peptide blockers can result in considerable modulation of the natural blocker-channel binding profile yielding selective fluorescent ligands of certain channels.

scholarly journals Pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines to develop functionalized ligands to target adenosine receptors: fluorescent ligands as an example

MedChemComm ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 1094-1108 ◽  
Author(s):  
Stephanie Federico ◽  
Enrico Margiotta ◽  
Silvia Paoletta ◽  
Sonja Kachler ◽  
Karl-Norbert Klotz ◽  
...  
Keyword(s):  
Adenosine Receptor ◽  
Adenosine Receptors ◽  
Receptor Antagonists ◽  
Fluorescent Ligands ◽  
Functionalized Ligands

A series of adenosine receptor antagonists bearing a reactive linker was developed.

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