scholarly journals Terahertz cross-correlation spectroscopy driven by incoherent light from a superluminescent diode

2019 ◽  
Vol 27 (9) ◽  
pp. 12659 ◽  
Author(s):  
Daniel Molter ◽  
Michael Kolano ◽  
Georg von Freymann
Keyword(s):  
Cross Correlation ◽  
Correlation Spectroscopy ◽  
Incoherent Light ◽  
Superluminescent Diode

scholarly journals Fluorescence Cross-Correlation Spectroscopy Yields True Affinity and Binding Kinetics of Plasmodium Lactate Transport Inhibitors

2021 ◽  
Vol 14 (8) ◽  
pp. 757
Author(s):  
Iga Jakobowska ◽  
Frank Becker ◽  
Stefano Minguzzi ◽  
Kerrin Hansen ◽  
Björn Henke ◽  
...  
Keyword(s):  
Rate Constants ◽  
Cross Correlation ◽  
Fluorescent Protein ◽  
Correlation Spectroscopy ◽  
Confocal Imaging ◽  
Binding Kinetics ◽  
Acceptor Site ◽  
Lactate Transport ◽  
Entry Site ◽  
Hydrogen Bond Acceptor

Blocking lactate export in the parasitic protozoan Plasmodium falciparum is a novel strategy to combat malaria. We discovered small drug-like molecules that inhibit the sole plasmodial lactate transporter, PfFNT, and kill parasites in culture. The pentafluoro-3-hydroxy-pent-2-en-1-one BH296 blocks PfFNT with nanomolar efficiency but an in vitro selected PfFNT G107S mutation confers resistance against the drug. We circumvented the mutation by introducing a nitrogen atom as a hydrogen bond acceptor site into the aromatic ring of the inhibitor yielding BH267.meta. The current PfFNT inhibitor efficiency values were derived from yeast-based lactate transport assays, yet direct affinity and binding kinetics data are missing. Here, we expressed PfFNT fused with a green fluorescent protein in human embryonic kidney cells and generated fluorescent derivatives of the inhibitors, BH296 and BH267.meta. Using confocal imaging, we confirmed the location of the proposed binding site at the cytosolic transporter entry site. We then carried out fluorescence cross-correlation spectroscopy measurements to assign true Ki-values, as well as kon and koff rate constants for inhibitor binding to PfFNT wildtype and the G107S mutant. BH296 and BH267.meta gave similar rate constants for binding to PfFNT wildtype. BH296 was inactive on PfFNT G107S, whereas BH267.meta bound the mutant protein albeit with weaker affinity than to PfFNT wildtype. Eventually, using a set of PfFNT inhibitor compounds, we found a robust correlation of the results from the biophysical FCCS binding assay to inhibition data of the functional transport assay.

Dual-color fluorescence cross-correlation spectroscopy on a planar optofluidic chip

Lab on a Chip ◽  
2011 ◽  
Vol 11 (8) ◽  
pp. 1502 ◽  
Author(s):  
A. Chen ◽  
M. M. Eberle ◽  
E. J. Lunt ◽  
S. Liu ◽  
K. Leake ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Correlation Spectroscopy ◽  
Dual Color ◽  
Optofluidic Chip

scholarly journals Fluorescence Correlation and Cross-Correlation Spectroscopy Unveil Cytoplasmic mRNP Composition and Dynamics

2020 ◽  
Author(s):  
Àngels Mateu-Regué ◽  
Jan Christiansen ◽  
Christian Hellriegel ◽  
Finn Cilius Nielsen
Keyword(s):  
Life Cycle ◽  
Dynamic Analysis ◽  
Cross Correlation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Correlation Spectroscopy ◽  
Live Cells ◽  
Macromolecular Complexes ◽  
Fluorescence Correlation ◽  
Macromolecular Composition

ABSTRACTUnderstanding the mRNA life cycle requires analysis of the dynamic macromolecular composition and stoichiometry of mRNPs. Fluorescence correlation and cross-correlation spectroscopy (FCS and FCCS) are appealing technologies to study mRNP complexes because they readily provide information about the molecular composition, stoichiometry, heterogeneity and dynamics of the particles. We developed FCS protocols for analysis of live cells and cellular lysates, and demonstrate the feasibility of analysing common cytoplasmic mRNPs composed of core factor YBX1, IMPs (or IGF2BPs) and their interactions with other RNA binding proteins such as PABPC1, ELAVL2 (HuB), STAU1 and FMRP. FCCS corroborated previously reported RNA dependent interactions between the factors and provided an estimate of the relative overlap between the factors in the mRNPs. In this way FCS and FCCS provide a new and useful approach for the quantitative and dynamic analysis of mRNP macromolecular complexes that may complement current biochemical approaches.

scholarly journals Multi-color fluorescence fluctuation spectroscopy in living cells via spectral detection

2020 ◽  
Author(s):  
Valentin Dunsing ◽  
Annett Petrich ◽  
Salvatore Chiantia
Keyword(s):  
Correlation Analysis ◽  
Influenza A ◽  
Cross Correlation ◽  
Matrix Protein ◽  
Living Cells ◽  
Correlation Spectroscopy ◽  
Image Correlation ◽  
Fluorescence Fluctuation Spectroscopy ◽  
Diffusion Dynamics ◽  
Cross Correlation Analysis

AbstractFluorescence fluctuation spectroscopy provides a powerful toolbox to quantify transport dynamics and interactions between biomolecules in living cells. For example, cross-correlation analysis of spectrally separated fluctuations allows the investigation of inter-molecular interactions. This analysis is conventionally limited to two fluorophore species that are excited with a single or two different laser lines and detected in two non-overlapping spectral channels. However, signaling pathways in biological systems often involve interactions between multiple biomolecules, e.g. formation of ternary or quaternary protein complexes. Here, we present a methodology to investigate such interactions at the plasma membrane (PM) of cells, as encountered for example in viral assembly or receptor-ligand interactions. To this aim, we introduce scanning fluorescence spectral correlation spectroscopy (SFSCS), a combination of scanning fluorescence correlation spectroscopy with spectrally resolved detection and decomposition. We first demonstrate that SFSCS allows cross-talk-free cross-correlation analysis of PM-associated proteins labeled with strongly overlapping fluorescent proteins (FPs), such as mEGFP and mEYFP, excited with a single excitation line. We then verify the applicability of SFSCS for quantifying diffusion dynamics and protein oligomerization (based on molecular brightness analysis) of two protein species tagged with spectrally overlapping FPs. Adding a second laser line, we demonstrate the possibility of three- and four-species (cross-) correlation analysis using mApple and mCherry2, as examples of strongly overlapping FP tags in the red spectral region. Next, we apply this scheme to investigate the interactions of influenza A virus (IAV) matrix protein 2 (M2) with two cellular host factors simultaneously. Using the same set of fluorophores, we furthermore extend the recently presented raster spectral image correlation spectroscopy (RSICS) approach to four species analysis, successfully demonstrating multiplexed RSICS measurements of protein interactions in the cell cytoplasm. Finally, we apply RSICS to investigate the assembly of the ternary IAV polymerase complex and report a 2:2:2 stoichiometry of these protein assemblies in the nucleus of living cells.

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