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Life on the molecular scale is based on a complex interplay of biomolecules under which the ability of binding is crucial. Fluorescence based two-color coincidence detection (TCCD) is commonly used to characterize molecular binding, but suffers from an underestimation of coincident events. Here, we introduce a brightness-gated TCCD which overcomes this limitation and benchmark our approach with two custom-made calibration samples. Applied to a cell-free protein synthesis assay, brightness-gated TCCD unraveled a previously disregarded mode of translation initiation in bacteria.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897966 | PMC |
http://dx.doi.org/10.1038/s42003-019-0709-7 | DOI Listing |
Chembiochem
August 2025
RWTH Aachen University, I. Physikalisches Institut (IA), AG Biophysik, 52074, Aachen, Germany.
Due to the extreme sensitivity and the intrinsic selectivity of fluorescence techniques, high-affinity binding can be measured even at extremely low molecule concentrations in the picomolar range. In particular, modern advanced techniques with fluorescence microscopes have provided considerable methodological advancements in recent years. Here, a brief description of the basic physical principles of fluorescence detection and its experimental measurement setups are provided.
View Article and Find Full Text PDFJ Chem Phys
April 2025
State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
We experimentally investigate the dissociative multiple ionization of argon trimers and tetramers induced by relative phase-controlled linearly and elliptically polarized two-color femtosecond laser fields. The momentum distributions and kinetic energy releases of the resulting fragments from various channels are measured in coincidence. The observed anisotropic momentum distributions indicate a preference for triple and quadruple ionization of argon trimers when one of the argon atoms is aligned parallel to the laser field polarization.
View Article and Find Full Text PDFJ Chem Phys
February 2025
State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
We present an experimental investigation aimed at tracking and controlling the dissociative ionization of formic acid molecules using intense femtosecond laser pulses. The resulting ionic products, formyl and hydroxyl radicals, are measured in coincidence. By analyzing the kinetic energy release spectra of these ionic radicals as a function of the time delay between the pump and probe laser pulses, we identify two distinct formation pathways.
View Article and Find Full Text PDFJ Chem Phys
December 2024
State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
Using ion-ion coincidence measurements, we experimentally investigate the dissociative triple ionization of argon dimers in relative phase controlled elliptically polarized two-color femtosecond laser fields. By examining the kinetic energy release-dependent momentum angular distribution of the ejected ionic fragments, two distinct pathways, each associated with different intermediates, are identified. Control over the emission directions of the ionic fragments is achieved by varying the relative phase of the elliptical two-color laser fields.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
May 2024
Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
Hyperphosphorylation and aggregation of the protein tau play key roles in the development of Alzheimer's disease (AD). While the molecular structure of the filamentous tau aggregates has been determined to atomic resolution, there is far less information available about the smaller, soluble aggregates, which are believed to be more toxic. Traditional techniques are limited to bulk measures and struggle to identify individual aggregates in complex biological samples.
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