Dna Force Extension
Dna Force Extension - Related Videos
08:48
Stretching Short Sequences of DNA with Constant Force Axial Optical Tweezers
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Cited by 5 •
2011
We illustrate the use of a constant force axial optical tweezers to explore the mechanical properties of short DNA molecules. By stretching DNA axially, we minimize steric hindrances and artifacts arising in conventional lateral manipulation, allowing us to study DNA molecules as short as ~100 nm.
15:28
Primer Extension Capture: Targeted Sequence Retrieval from Heavily Degraded DNA Sources
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Cited by 41 •
2009
We present a method of targeted ancient DNA sequence retrieval, which we used to reconstruct the complete mitochondrial genomes of five Neandertal individuals. Comparison of these sequences with present day humans suggests that Neandertals had a long term low effective population size.
08:30
Visualization of Recombinant DNA and Protein Complexes Using Atomic Force Microscopy
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Cited by 6 •
2011
A tapping mode atomic force microscope (AFM) method for the visualization of plasmid DNA, cytoplasmic proteins, and DNA-protein complexes is described. The method includes alternate approaches for preparing samples for AFM imaging following biochemical manipulation. DNA containing specific protein interacting regions are observed in near-physiologic buffer conditions.
05:58
Using DNA-Based Tension Probes to Assess Receptor Forces Applied by Immune Cells
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2025
The video demonstrates a method for assessing receptor forces applied by immune cells using polyethylene glycol-anchored gold nanoparticles and DNA hairpin tension probes. CD8-positive T cell interactions trigger probe unfolding, emitting fluorescence while locking strands sustain the signal for quantifying the forces applied by immune cells.
10:59
Atomic Force Microscopy Investigations of DNA Lesion Recognition in Nucleotide Excision Repair
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Cited by 2 •
2017
Here, the study of different DNA lesion recognition approaches via single molecule AFM imaging is demonstrated with the nucleotide excision repair system as an example. The procedures of DNA and protein sample preparations and experimental as well as analytical details for the AFM experiments are described.
FAQs
Different portions of a DNA force-extension curve correspond to distinct mechanical behaviors. Entropic elasticity describes one response, while structural transitions indicate a change in the molecule’s behavior as force increases. At higher forces, overstretching provides another recognizable regime. Separating these features helps researchers interpret whether a result reflects elasticity or force-induced structural change.
Researchers can use the relationship between applied tension and molecular extension to quantify DNA stiffness and bending. These properties describe how readily the molecule changes shape under mechanical load, rather than simply reporting its length. The measurements therefore provide a physical characterization of DNA that complements studies of genome organization and protein-mediated remodeling.
Because the method measures DNA while force is controlled, protein binding, packaging, or remodeling can be examined through effects on the measured mechanical response. The resulting data can show how proteins influence DNA extension, stiffness, or structural behavior under tension. This connects molecular interactions with larger processes that organize or process genomes.
Single-molecule experiments use either optical tweezers or magnetic tweezers to apply controlled tension to DNA and measure its extension. The central readout is the force-dependent change in molecular length. Researchers can then examine the resulting curve for features associated with elasticity, structural transitions, and higher-force overstretching.
It is especially useful when a biological question depends on DNA mechanics. Applications include studying genome organization, replication, transcription, and the actions of proteins that bind, package, or remodel DNA. By measuring mechanical behavior at the single-molecule level, researchers can connect molecular-scale forces with processes relevant to cellular DNA.
Relating the measurements to polymer physics turns changes in molecular length into quantitative information about DNA’s physical properties. The results can address stiffness, bending, entropic elasticity, structural transitions, and overstretching, while also informing how DNA behaves in cellular settings. This bridge helps interpret genome organization and the mechanical consequences of replication, transcription, and protein activity.