High pressure single-molecule FRET studies of the lysine riboswitch: cationic and osmolytic effects on pressure induced denaturation

2020 ◽  
Vol 22 (28) ◽  
pp. 15853-15866 ◽  
Author(s):  
Hsuan-Lei Sung ◽  
David J. Nesbitt
Keyword(s):  
High Pressure ◽  
Single Molecule ◽  
Pressure Effects ◽  
Protective Mechanisms ◽  
Single Molecule Fret ◽  
Single Molecule Studies

Protective mechanisms of the piezolyte trimethylamine N-oxide counteracting the pressure effects are revealed by single molecule studies at extreme pressures.

Quantitative structural information from single-molecule FRET

2015 ◽  
Vol 184 ◽  
pp. 117-129 ◽  
Author(s):  
M. Beckers ◽  
F. Drechsler ◽  
T. Eilert ◽  
J. Nagy ◽  
J. Michaelis
Keyword(s):  
Single Molecule ◽  
Structural Information ◽  
Monte Carlo Sampling ◽  
Dye Molecules ◽  
Distance Information ◽  
Single Molecule Fret ◽  
Single Molecule Studies ◽  
Archaeal Transcription ◽  
Short Time ◽  
Fluorescence Energy

Single-molecule studies can be used to study biological processes directly and in real-time. In particular, the fluorescence energy transfer between reporter dye molecules attached to specific sites on macromolecular complexes can be used to infer distance information. When several measurements are combined, the information can be used to determine the position and conformation of certain domains with respect to the complex. However, data analysis schemes that include all experimental uncertainties are highly complex, and the outcome depends on assumptions about the state of the dye molecules. Here, we present a new analysis algorithm using Bayesian parameter estimation based on Markov Chain Monte Carlo sampling and parallel tempering termed Fast-NPS that can analyse large smFRET networks in a relatively short time and yields the position of the dye molecules together with their respective uncertainties. Moreover, we show what effects different assumptions about the dye molecules have on the outcome. We discuss the possibilities and pitfalls in structure determination based on smFRET using experimental data for an archaeal transcription pre-initiation complex, whose architecture has recently been unravelled by smFRET measurements.

scholarly journals Correction: High pressure single-molecule FRET studies of the lysine riboswitch: cationic and osmolytic effects on pressure induced denaturation

2020 ◽  
Vol 22 (29) ◽  
pp. 17008-17009
Author(s):  
Hsuan-Lei Sung ◽  
David J. Nesbitt
Keyword(s):  
High Pressure ◽  
Single Molecule ◽  
Chem Phys ◽  
Single Molecule Fret ◽  
Phys Chem Chem Phys

Correction for ‘High pressure single-molecule FRET studies of the lysine riboswitch: cationic and osmolytic effects on pressure induced denaturation’ by Hsuan-Lei Sung et al., Phys. Chem. Chem. Phys., 2020, DOI: 10.1039/d0cp01921f.

scholarly journals Yeast Chd1p remodels nucleosomes with unique DNA unwrapping and translocation dynamics

2018 ◽  
Author(s):  
Jaewon Kirk ◽  
Ju Yeon Lee ◽  
Yejin Lee ◽  
Chanshin Kang ◽  
Soochul Shin ◽  
...  
Keyword(s):  
Single Molecule ◽  
Atp Hydrolysis ◽  
Chromatin Remodeler ◽  
Base Pairs ◽  
Nucleosome Remodeling ◽  
Chromatin Remodelers ◽  
Histone Octamer ◽  
Single Molecule Fret ◽  
Single Molecule Studies ◽  
Dna Unwrapping

AbstractChromodomain-helicase-DNA-binding protein 1 (CHD1) remodels chromatin by translocating nucleosomes along DNA, but its mechanism remains poorly understood. Here, we employ a single-molecule fluorescence approach to characterize nucleosome remodeling by yeast CHD1 (Chd1p). We show that Chd1p translocates nucleosomes in steps of multiple base pairs per ATP. ATP binding to Chd1p induces a transient unwrapping of the exit-side DNA, and facilitates nucleosome translocation. ATP hydrolysis induces nucleosome translocation, which is followed by the rewrapping upon the release of the hydrolyzed nucleotide. Multiple Chd1ps binding to a single nucleosome sequentially moves a histone octamer with a preference to the center of DNA fragments, suggesting a new mechanism for regularly spaced nucleosome generation by Chd1p. Our results reveal the unique mechanism by which Chd1p remodels nucleosomes.Significance StatementThere are four major ATP-dependent chromatin remodeler families: SWI/SNF, ISWI, CHD, and INO80/SWR1. The remodeling mechanisms of SWI/SNF and ISWI chromatin remodelers have been elucidated through extensive single-molecule studies, but it remains poorly understood how CHD chromatin remodeler operate. We use single-molecule FRET techniques, and show that Yeast CHD1 uses unique mechanisms to remodel a nucleosome.

scholarly journals Encoding Multiple Virtual Signals in DNA Barcodes with Single-Molecule FRET

Nano Letters ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1694-1701 ◽  
Author(s):  
Sung Hyun Kim ◽  
Hyunwoo Kim ◽  
Hawoong Jeong ◽  
Tae-Young Yoon
Keyword(s):  
Single Molecule ◽  
Dna Barcodes ◽  
Single Molecule Fret

Single-Molecule FRET-Based Dynamic DNA Sensor

ACS Sensors ◽  
2021 ◽  
Author(s):  
Anoja Megalathan ◽  
Kalani M. Wijesinghe ◽  
Soma Dhakal
Keyword(s):  
Single Molecule ◽  
Dna Sensor ◽  
Single Molecule Fret

scholarly journals Hopping and Flipping of RNA Polymerase on DNA during Recycling for Reinitiation after Intrinsic Termination in Bacterial Transcription

2021 ◽  
Vol 22 (5) ◽  
pp. 2398
Author(s):  
Wooyoung Kang ◽  
Seungha Hwang ◽  
Jin Young Kang ◽  
Changwon Kang ◽  
Sungchul Hohng
Keyword(s):  
Single Molecule ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Facilitated Diffusion ◽  
One Dimensional ◽  
Bacterial Transcription ◽  
Fluorescence Measurements ◽  
Dimensional Diffusion ◽  
Single Molecule Studies ◽  
Hopping Diffusion

Two different molecular mechanisms, sliding and hopping, are employed by DNA-binding proteins for their one-dimensional facilitated diffusion on nonspecific DNA regions until reaching their specific target sequences. While it has been controversial whether RNA polymerases (RNAPs) use one-dimensional diffusion in targeting their promoters for transcription initiation, two recent single-molecule studies discovered that post-terminational RNAPs use one-dimensional diffusion for their reinitiation on the same DNA molecules. Escherichia coli RNAP, after synthesizing and releasing product RNA at intrinsic termination, mostly remains bound on DNA and diffuses in both forward and backward directions for recycling, which facilitates reinitiation on nearby promoters. However, it has remained unsolved which mechanism of one-dimensional diffusion is employed by recycling RNAP between termination and reinitiation. Single-molecule fluorescence measurements in this study reveal that post-terminational RNAPs undergo hopping diffusion during recycling on DNA, as their one-dimensional diffusion coefficients increase with rising salt concentrations. We additionally find that reinitiation can occur on promoters positioned in sense and antisense orientations with comparable efficiencies, so reinitiation efficiency depends primarily on distance rather than direction of recycling diffusion. This additional finding confirms that orientation change or flipping of RNAP with respect to DNA efficiently occurs as expected from hopping diffusion.

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