Magnetic Tweezers Force Spectroscopy

2014 ◽  
pp. 481-490
Author(s):  
Eric Galburt
Keyword(s):  
Force Spectroscopy ◽  
Magnetic Tweezers

scholarly journals Denaturation transition of stretched DNA

2013 ◽  
Vol 41 (2) ◽  
pp. 639-645 ◽  
Author(s):  
Andreas Hanke
Keyword(s):  
Nucleic Acids ◽  
Single Molecule ◽  
Force Spectroscopy ◽  
Magnetic Tweezers ◽  
Present Review ◽  
Dna Molecules ◽  
Force Measurements ◽  
Force Extension ◽  
Atomic Force Spectroscopy ◽  
Atomic Force

In the last two decades, single-molecule force measurements using optical and magnetic tweezers and atomic force spectroscopy have dramatically expanded our knowledge of nucleic acids and proteins. These techniques characterize the force on a biomolecule required to produce a given molecular extension. When stretching long DNA molecules, the observed force–extension relationship exhibits a characteristic plateau at approximately 65 pN where the DNA may be extended to almost twice its B-DNA length with almost no increase in force. In the present review, I describe this transition in terms of the Poland–Scheraga model and summarize recent related studies.

scholarly journals Bioconjugation Strategies for Connecting Proteins to DNA-Linkers for Single-Molecule Force-Based Experiments

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2424
Author(s):  
Lyan M. van der Sleen ◽  
Katarzyna M. Tych
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Optical Tweezers ◽  
Single Molecule ◽  
Short Range ◽  
Force Spectroscopy ◽  
Magnetic Tweezers ◽  
Single Molecule Force Spectroscopy ◽  
Force Microscopy ◽  
Atomic Force

The mechanical properties of proteins can be studied with single molecule force spectroscopy (SMFS) using optical tweezers, atomic force microscopy and magnetic tweezers. It is common to utilize a flexible linker between the protein and trapped probe to exclude short-range interactions in SMFS experiments. One of the most prevalent linkers is DNA due to its well-defined properties, although attachment strategies between the DNA linker and protein or probe may vary. We will therefore provide a general overview of the currently existing non-covalent and covalent bioconjugation strategies to site-specifically conjugate DNA-linkers to the protein of interest. In the search for a standardized conjugation strategy, considerations include their mechanical properties in the context of SMFS, feasibility of site-directed labeling, labeling efficiency, and costs.

scholarly journals Modular, ultra-stable, and highly parallel protein force spectroscopy in magnetic tweezers using peptide linkers

2018 ◽  
Author(s):  
Achim Löf ◽  
Philipp U Walker ◽  
Steffen M Sedlak ◽  
Tobias Obser ◽  
Maria A Brehm ◽  
...  
Keyword(s):  
Single Molecule ◽  
Force Spectroscopy ◽  
Magnetic Tweezers ◽  
Protein Domain ◽  
High Yield ◽  
Primary Hemostasis ◽  
Wide Range ◽  
And Function ◽  
Von Willebrand

Single-molecule force spectroscopy has provided unprecedented insights into protein folding, force-regulation, and function. Here, we present a modular magnetic tweezers force spectroscopy approach that uses elastin-like polypeptide linkers to provide a high yield of protein tethers. Our approach extends protein force spectroscopy into the low force (<1 pN) regime and enables ultra-stable measurements on many molecules in parallel. We present (un-)folding data for the single protein domain ddFLN4 and for the large multi-domain dimeric protein von Willebrand factor (VWF) that is critically involved in primary hemostasis. The measurements reveal exponential force-dependencies of unfolding and refolding rates, directly resolve the stabilization of the VWF A2 domain by Ca2+, and discover transitions in the VWF C-domain stem at low forces that likely constitute the first steps of VWF activation in vivo. Our modular attachment approach will enable precise and multiplexed force spectroscopy measurements for a wide range of proteins in the physiologically relevant force regime.

scholarly journals Characterization of G-Quadruplexes Folding/Unfolding Dynamics and Interactions with Proteins from Single-Molecule Force Spectroscopy

Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1579
Author(s):  
Yuanlei Cheng ◽  
Yashuo Zhang ◽  
Huijuan You
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Molecular Mechanisms ◽  
Force Spectroscopy ◽  
Magnetic Tweezers ◽  
Single Molecule Force Spectroscopy ◽  
Force Microscopy ◽  
Multiple Structures ◽  
Regulation Functions ◽  
Nucleic Acid Structures

G-quadruplexes (G4s) are stable secondary nucleic acid structures that play crucial roles in many fundamental biological processes. The folding/unfolding dynamics of G4 structures are associated with the replication and transcription regulation functions of G4s. However, many DNA G4 sequences can adopt a variety of topologies and have complex folding/unfolding dynamics. Determining the dynamics of G4s and their regulation by proteins remains challenging due to the coexistence of multiple structures in a heterogeneous sample. Here, in this mini-review, we introduce the application of single-molecule force–spectroscopy methods, such as magnetic tweezers, optical tweezers, and atomic force microscopy, to characterize the polymorphism and folding/unfolding dynamics of G4s. We also briefly introduce recent studies using single-molecule force spectroscopy to study the molecular mechanisms of G4-interacting proteins.

scholarly journals Multiplexed protein force spectroscopy reveals equilibrium protein folding dynamics and the low-force response of von Willebrand factor

2019 ◽  
Vol 116 (38) ◽  
pp. 18798-18807 ◽  
Author(s):  
Achim Löf ◽  
Philipp U. Walker ◽  
Steffen M. Sedlak ◽  
Sophia Gruber ◽  
Tobias Obser ◽  
...  
Keyword(s):  
Protein Folding ◽  
Optical Tweezers ◽  
Von Willebrand Factor ◽  
Force Spectroscopy ◽  
Magnetic Tweezers ◽  
Modular Approach ◽  
Wide Range ◽  
Specific Attachment ◽  
Von Willebrand ◽  
Willebrand Factor

Single-molecule force spectroscopy has provided unprecedented insights into protein folding, force regulation, and function. So far, the field has relied primarily on atomic force microscope and optical tweezers assays that, while powerful, are limited in force resolution, throughput, and require feedback for constant force measurements. Here, we present a modular approach based on magnetic tweezers (MT) for highly multiplexed protein force spectroscopy. Our approach uses elastin-like polypeptide linkers for the specific attachment of proteins, requiring only short peptide tags on the protein of interest. The assay extends protein force spectroscopy into the low force (<1 pN) regime and enables parallel and ultra-stable measurements at constant forces. We present unfolding and refolding data for the small, single-domain protein ddFLN4, commonly used as a molecular fingerprint in force spectroscopy, and for the large, multidomain dimeric protein von Willebrand factor (VWF) that is critically involved in primary hemostasis. For both proteins, our measurements reveal exponential force dependencies of unfolding and refolding rates. We directly resolve the stabilization of the VWF A2 domain by Ca2+ and discover transitions in the VWF C domain stem at low forces that likely constitute the first steps of VWF’s mechano-activation. Probing the force-dependent lifetime of biotin–streptavidin bonds, we find that monovalent streptavidin constructs with specific attachment geometry are significantly more force stable than commercial, multivalent streptavidin. We expect our modular approach to enable multiplexed force-spectroscopy measurements for a wide range of proteins, in particular in the physiologically relevant low-force regime.

scholarly journals Freely Orbiting Magnetic Tweezers: A New Twist on Single Molecule Force Spectroscopy

2011 ◽  
Vol 100 (3) ◽  
pp. 23a-24a
Author(s):  
Matthew J. Wiggin ◽  
Jan Lipfert ◽  
Roeland van Wijk ◽  
Jakob Kerssemakers ◽  
Nynke Dekker
Keyword(s):  
Single Molecule ◽  
Force Spectroscopy ◽  
Magnetic Tweezers ◽  
Single Molecule Force Spectroscopy
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