Single-Molecule Studies on DNA and RNA

ChemPhysChem ◽  
2005 ◽  
Vol 6 (12) ◽  
pp. 2458-2471 ◽  
Author(s):  
Karl Otto Greulich
Keyword(s):  
Single Molecule ◽  
Dna And Rna ◽  
Single Molecule Studies

Single-molecule studies of DNA and RNA four-way junctions

2004 ◽  
Vol 32 (1) ◽  
pp. 41-45 ◽  
Author(s):  
S.A. McKinney ◽  
E. Tan ◽  
T.J. Wilson ◽  
M.K. Nahas ◽  
A.-C. Déclais ◽  
...  
Keyword(s):  
Single Molecule ◽  
Active Site ◽  
Dynamic Structure ◽  
Holliday Junctions ◽  
Site Formation ◽  
Structural Element ◽  
Fluorescence Studies ◽  
Definitive Evidence ◽  
Dna And Rna ◽  
Single Molecule Studies

Branched helical junctions are common in nucleic acids. In DNA, the four-way junction (Holliday junction) is an essential intermediate in homologous recombination and is a highly dynamic structure, capable of stacking conformer transitions and branch migration. Our single-molecule fluorescence studies provide unique insight into the energy landscape of Holliday junctions by visualizing these processes directly. In the hairpin ribozyme, an RNA four-way junction is an important structural element that enhances active-site formation by several orders of magnitude. Our single-molecule studies suggest a plausible mechanism for how the junction achieves this remarkable feat; the structural dynamics of the four-way junction bring about frequent contacts between the loops that are needed to form the active site. The most definitive evidence for this is the observation of three-state folding in single-hairpin ribozymes, the intermediate state of which is populated due to the intrinsic properties of the junction.

Single-Molecule Studies of Nucleic Acids and Their Proteins

2018 ◽  
Author(s):  
David Bensimon ◽  
Vincent Croquette ◽  
Jean-François Allemand ◽  
Xavier Michalet ◽  
Terence Strick
Keyword(s):  
Single Molecule ◽  
Protein Interactions ◽  
Radiative Decay ◽  
Dynamic Properties ◽  
Rna Polymerases ◽  
Chiral Discrimination ◽  
Triplet States ◽  
Comprehensive Overview ◽  
Dna And Rna ◽  
Single Molecule Studies

This book presents a comprehensive overview of the foundations of single-molecule studies, based on manipulation of the molecules and observation of these with fluorescent probes. It first discusses the forces present at the single-molecule scale, the methods to manipulate them, and their pros and cons. It goes on to present an introduction to single-molecule fluorescent studies based on a quantum description of absorption and emission of radiation due to Einstein. Various considerations in the study of single molecules are introduced (including signal to noise, non-radiative decay, triplet states, etc.) and some novel super-resolution methods are sketched. The elastic and dynamic properties of polymers, their relation to experiments on DNA and RNA, and the structural transitions observed in those molecules upon stretching, twisting, and unzipping are presented. The use of these single-molecule approaches for the investigation of DNA–protein interactions is highlighted via the study of DNA and RNA polymerases, helicases, and topoisomerases. Beyond the confirmation of expected mechanisms (e.g., the relaxation of DNA torsion by topoisomerases in quantized steps) and the discovery of unexpected ones (e.g., strand-switching by helicases, DNA scrunching by RNA polymerases, and chiral discrimination by bacterial topoII), these approaches have also fostered novel (third generation) sequencing technologies.

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.

Breaking Down the Supramolecular Ensemble: Single-Molecule Studies of the Concentration Dependence of Main-Chain Supramolecular Polymer Molecular Weight Distributions on Surfaces

2010 ◽  
Vol 63 (4) ◽  
pp. 624
Author(s):  
Michael J. Serpe ◽  
Jason R. Whitehead ◽  
Stephen L. Craig
Keyword(s):  
Molecular Weight ◽  
Single Molecule ◽  
Monomer Concentration ◽  
Supramolecular Polymer ◽  
Force Microscopy ◽  
Molecular Weight Distributions ◽  
Atomic Force ◽  
Multi Stage ◽  
Single Molecule Studies ◽  
Supramolecular Ensemble

Single molecule atomic force microscopy (AFM) studies of oligonucleotide-based supramolecular polymers on surfaces are used to examine the molecular weight distribution of the polymers formed between a functionalized surface and an AFM tip as a function of monomer concentration. For the concentrations examined here, excellent agreement with a multi-stage open association model of polymerization is obtained, without the need to invoke additional contributions from secondary steric interactions at the surface.

scholarly journals Single-Molecule Studies of the Na+/K+-ATPase

2011 ◽  
Vol 100 (3) ◽  
pp. 464a
Author(s):  
Promod R. Pratap ◽  
Gregor Heiss ◽  
Martin Sikor ◽  
Don C. Lamb ◽  
Max Burnett
Keyword(s):  
Single Molecule ◽  
Single Molecule Studies

scholarly journals Single Molecule Studies of DNA-Binding Proteins: Development of New Covalent DNA Anchoring Techniques for the Study of Rupture Forces of Replication Blocks

2014 ◽  
Vol 106 (2) ◽  
pp. 394a
Author(s):  
Richard Janissen ◽  
Bojk A. Berghuis ◽  
Orkide Ordu ◽  
Max M. Wink ◽  
David Dulin ◽  
...  
Keyword(s):  
Dna Binding ◽  
Single Molecule ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Single Molecule Studies
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