49 Result(s)
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Protocol
Introduction to Optical Tweezers: Background, System Designs, and Applications
Optical tweezers are a means to manipulate objects with light. With the technique, microscopically small objects can be held and steered, allowing for accurate measurement of the forces applied to these object...
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Single-Molecule Fluorescence Imaging of DNA Replication Stalling at Sites of Nucleoprotein Complexes
DNA replication in cells occurs on crowded and often damaged template DNA, forming potentially deleterious roadblocks to the progressing replication fork. Numerous tools have been developed to investigate the ...
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Protein Tethering for Single-Molecule Force Spectroscopy
Molecular manipulation by optical tweezers is a central technique to study the folded states of individual proteins and how they depend on interactions with molecules including DNA, ligands, and other proteins...
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Measuring αβ T-Cell Receptor-Mediated Mechanosensing Using Optical Tweezers Combined with Fluorescence Imaging
T-cell antigen receptors (TCRs) are mechanosensors, which initiate a signaling cascade upon ligand recognition resulting in T-cell differentiation, homeostasis, effector and regulatory functions. An optical tr...
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Art Ashkin and the Origins of Optical Trap** and Particle Manipulation
A brief history of optical forces, the invention of optical tweezers, and their application to biological problems.
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Protocol
Angular Optical Trap** to Directly Measure DNA Torsional Mechanics
Angular optical trap** (AOT) is a powerful technique that permits direct angular manipulation of a trapped particle with simultaneous measurement of torque and rotation, while also retaining the capabilities...
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Protocol
Probing the Interaction Between Chromatin and Chromatin-Associated Complexes with Optical Tweezers
Single-molecule force spectroscopy is a powerful tool to analyze the architecture and interaction of large macromolecular assemblies that are refractory to high-resolution structural interrogations. Here, we d...
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One-Dimensional STED Microscopy in Optical Tweezers
Optical tweezers and fluorescence microscopy are powerful methods for investigating the mechanical and structural properties of biomolecules and for studying the dynamics of the biomolecular processes that the...
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CRISPR/Cas9 On- and Off-Target Activity Using Correlative Force and Fluorescence Single-Molecule Microscopy
The discovery of CRISPR/Cas9 as an easily programmable endonuclease heralds a new era of genetic manipulation. With this comes the prospect of novel gene therapy approaches, and the potential to cure previousl...
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High-Resolution Optical Tweezers Combined with Multicolor Single-Molecule Microscopy
We present an instrument that combines high-resolution optical tweezers and multicolor confocal fluorescence spectroscopy. Biological macromolecules exhibit complex conformation and stoichiometry changes in co...
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Using Single-Molecule Optical Tweezers to Study the Conformational Cycle of the Hsp90 Molecular Chaperone
The heat shock protein 90 (Hsp90) family of chaperones are well-known, highly important components of the cellular systems which regulate protein homeostasis. Essential in eukaryotes, Hsp90s is also found in p...
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Single-Molecule Manipulation Study of Chaperoned SNARE Folding and Assembly with Optical Tweezers
Intracellular membrane fusion is primarily driven by coupled folding and assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). SNARE assembly is intrinsically inefficient an...
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Single-Molecule Studies on the Motion and Force Generation of the Kinesin-3 Motor KIF1A
KIF1A is a neuron-specific member of the kinesin-3 family of microtubule (MT) plus-end-directed motor proteins. It powers the migration of nuclei in differentiating brain stem cells and the transport of synapt...
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High-Speed Optical Traps Address Dynamics of Processive and Non-Processive Molecular Motors
Interactions between biological molecules occur on very different time scales, from the minutes of strong protein–protein bonds, down to below the millisecond duration of rapid biomolecular interactions. Confo...
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Catching the Conformational Wave: Measuring the Working Strokes of Protofilaments as They Curl Outward from Disassembling Microtubule Tips
Optical traps have enabled foundational studies of how mechanoenzymes such as kinesins and dynein motors walk along microtubules, how myosins move along F-actin, and how nucleic acid enzymes move along DNA or ...
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Quantifying the Interaction Strength Between Biopolymers
The cytoskeleton consists of three types of biopolymers—actin filaments, microtubules, and intermediate filaments—and the interplay between these components is essential for many cellular functions such as cel...
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The Invention of the Laser
In this chapter, I describe a scientific rivalry at Columbia University’s physics department in the days of the 1950s before and when the laser invented, and the race to build a laser eventually won by a scien...
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Synthesis of Germanium Nanospheres as High-Precision Optical Tweezers Probes
Force spectroscopy on single molecular machines generating piconewton forces is often performed using optical tweezers. Since trap** forces scale with the particle volume, piconewton-force measurements so fa...
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Force-Activated DNA Substrates for In Situ Generation of ssDNA and Designed ssDNA/dsDNA Structures in an Optical-Trap** Assay
Single-molecule force spectroscopy can precisely probe the biomechanical interactions of proteins that unwind duplex DNA and bind to and wrap around single-stranded (ss)DNA. Yet assembly of the required substr...
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Implementation of 3D Multi-Color Fluorescence Microscopy in a Quadruple Trap Optical Tweezers System
Recent advances in the design and measurement capabilities of optical tweezers instruments, and especially the combination with multi-color fluorescence detection, have accommodated a dramatic increase in the ...
