A Light-Up Fluorescence Resonance Energy Transfer Magnetic Aptamer-Sensor for Ultra-Sensitive Lung Cancer Exosome Detection

Author(s):  
Nanhang Zhu ◽  
Guohao Li ◽  
Juan Zhou ◽  
Yujia Zhang ◽  
Ke Kang ◽  
...  

In vitro liquid biopsy based on exosomes offers promising opportunities for fast and reliable detection of lung cancers. In this work, we present a fluorescence resonance energy transfer (FRET) magnetic...

Author(s):  
Nanhang Zhu ◽  
Guohao Li ◽  
Juan Zhou ◽  
Yujia Zhang ◽  
Ke Kang ◽  
...  

Correction for ‘A light-up fluorescence resonance energy transfer magnetic aptamer-sensor for ultra-sensitive lung cancer exosome detection’ by Nanhang Zhu et al., J. Mater. Chem. B, 2021, 9, 2483–2493, DOI: 10.1039/D1TB00046B.


2000 ◽  
Vol 6 (S2) ◽  
pp. 828-829
Author(s):  
M. L. Ruehr ◽  
D. S. Damron ◽  
M. Bond

The clustering of components of a signaling pathway at a specific subcellular location raises the local concentration of the appropriate messengers and serves to amplify the signal. The cAMP dependent-protein kinase (PKA) pathway is regulated by compartmentalization of its components. A-kinase anchoring proteins (AKAPs) tether PKA to specific subcellular sites, thus presumably increasing substrate specificity. Phosphorylation of the type II regulatory subunit of PKA (RII) increases its affinity for AKAPs in vitro (1). The purpose of this study was to investigate whether altering the phosphorylation state of RII in live cells changes its affinity for an AKAP. Specifically, we investigated the binding kinetics between Ht31, a peptide containing the PKA binding portion of an AKAP from human thyroid (2), and RII, in response to PKA activators or inhibitors.Fluorescence resonance energy transfer (FRET) was used to monitor binding events between RII and the catalytic subunit (C) of PKA, Ht31, or Ht31P, a mutated form of Ht31 which does not bind RII.


2011 ◽  
Vol 392 (1-2) ◽  
Author(s):  
Michael Börsch

Abstract Conformational changes of proteins can be monitored in real time by fluorescence resonance energy transfer (FRET). Two different fluorophores have to be attached to those protein domains which move during function. Distance fluctuations between the fluorophores are measured by relative fluorescence intensity changes or fluorescence lifetime changes. The rotary mechanics of the two motors of FoF1-ATP synthase have been studied in vitro by single-molecule FRET. The results are summarized and perspectives for other transport ATPases are discussed.


2005 ◽  
Vol 280 (23) ◽  
pp. 22549-22554 ◽  
Author(s):  
Yaodong Chen ◽  
Harold P. Erickson

We have developed an assay for the assembly of FtsZ based on fluorescence resonance energy transfer (FRET). We mutated an innocuous surface residue to cysteine and labeled separate pools with fluorescein (donor) and tetramethylrhodamine (acceptor). When the pools were mixed and GTP was added, assembly produced a FRET signal that was linearly proportional to FtsZ concentration from 0.7 μm (the critical concentration (Cc)) to 3 μm. At concentrations greater than 3 μm, an enhanced FRET signal was observed with both GTP and GDP, indicating additional assembly above this second Cc. This second Cc varied with Mg2+ concentration, whereas the 0.7 μmCc did not. We used the FRET assay to measure the kinetics of initial assembly by stopped flow. The data were fit by the simple kinetic model used previously: monomer activation, a weak dimer nucleus, and elongation, although with some differences in kinetic parameters from the L68W mutant. We then studied the rate of turnover at steady state by pre-assembling separate pools of donor and acceptor protofilaments. When the pools were mixed, a FRET signal developed with a half-time of 7 s, demonstrating a rapid and continuous disassembly and reassembly of protofilaments at steady state. This is comparable with the 9-s half-time for FtsZ turnover in vivo and the 8-s turnover time of GTP hydrolysis in vitro. Finally, we found that an excess of GDP caused disassembly of protofilaments with a half-time of 5 s. Our new data suggest that GDP does not exchange into intact protofilaments. Rather, our interpretation is that subunits are released following GTP hydrolysis, and then they exchange GDP for GTP and reassemble into new protofilaments, all on a time scale of 7 s. The mechanism may be related to the dynamic instability of microtubules.


2012 ◽  
Vol 12 (2) ◽  
pp. 322-329 ◽  
Author(s):  
Lei Wang ◽  
Martin Ciganda ◽  
Noreen Williams

ABSTRACT We have previously reported that the trypanosome-specific proteins P34 and P37 form a unique preribosomal complex with ribosomal protein L5 and 5S rRNA in the nucleoplasm. We hypothesize that this novel trimolecular complex is necessary for stabilizing 5S rRNA in Trypanosoma brucei and is essential for the survival of the parasite. In vitro quantitative analysis of the association between the proteins L5 and P34 is fundamental to our understanding of this novel complex and thus our ability to exploit its unique characteristics. Here we used in vitro fluorescence resonance energy transfer (FRET) to analyze the association between L5 and P34. First, we demonstrated that FRET can be used to confirm the association between L5 and P34. We then determined that the binding constant for L5 and P34 is 0.60 ± 0.03 μM, which is in the range of protein-protein binding constants for RNA binding proteins. In addition, we used FRET to identify the critical regions of L5 and P34 involved in the protein-protein association. We found that the N-terminal APK-rich domain and RNA recognition motif (RRM) of P34 and the L18 domain of L5 are important for the association of the two proteins with each other. These results provide us with the framework for the discovery of ways to disrupt this essential complex.


The Analyst ◽  
2018 ◽  
Vol 143 (3) ◽  
pp. 761-767 ◽  
Author(s):  
Lin Liu ◽  
Hua Zhang ◽  
Daqian Song ◽  
Zhenxin Wang

An upconversion nanoparticle-based fluorescence resonance energy transfer sensing platform has been developed for the caspase-3 activity detection in vitro and in cells.


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