Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.

The functional state of the genome is determined by its interactions with proteins that bind, modify, and move along the DNA. To determine the positions and binding strength of proteins localized on DNA we have developed a combined magnetic and optical tweezers apparatus that allows for both sensiti...

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Main Authors: Marijn T J van Loenhout, Iwijn De Vlaminck, Benedetta Flebus, Johan F den Blanken, Ludovit P Zweifel, Koen M Hooning, Jacob W J Kerssemakers, Cees Dekker
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3670887?pdf=render
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author Marijn T J van Loenhout
Iwijn De Vlaminck
Benedetta Flebus
Johan F den Blanken
Ludovit P Zweifel
Koen M Hooning
Jacob W J Kerssemakers
Cees Dekker
author_facet Marijn T J van Loenhout
Iwijn De Vlaminck
Benedetta Flebus
Johan F den Blanken
Ludovit P Zweifel
Koen M Hooning
Jacob W J Kerssemakers
Cees Dekker
author_sort Marijn T J van Loenhout
collection DOAJ
description The functional state of the genome is determined by its interactions with proteins that bind, modify, and move along the DNA. To determine the positions and binding strength of proteins localized on DNA we have developed a combined magnetic and optical tweezers apparatus that allows for both sensitive and label-free detection. A DNA loop, that acts as a scanning probe, is created by looping an optically trapped DNA tether around a DNA molecule that is held with magnetic tweezers. Upon scanning the loop along the λ-DNA molecule, EcoRI proteins were detected with ~17 nm spatial resolution. An offset of 33 ± 5 nm for the detected protein positions was found between back and forwards scans, corresponding to the size of the DNA loop and in agreement with theoretical estimates. At higher applied stretching forces, the scanning loop was able to remove bound proteins from the DNA, showing that the method is in principle also capable of measuring the binding strength of proteins to DNA with a force resolution of 0.1 pN/[Formula: see text]. The use of magnetic tweezers in this assay allows the facile preparation of many single-molecule tethers, which can be scanned one after the other, while it also allows for direct control of the supercoiling state of the DNA molecule, making it uniquely suitable to address the effects of torque on protein-DNA interactions.
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spelling doaj.art-0f3172dcf1a24a7a9a8a5e86a6f96c3c2022-12-21T18:30:51ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0186e6532910.1371/journal.pone.0065329Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.Marijn T J van LoenhoutIwijn De VlaminckBenedetta FlebusJohan F den BlankenLudovit P ZweifelKoen M HooningJacob W J KerssemakersCees DekkerThe functional state of the genome is determined by its interactions with proteins that bind, modify, and move along the DNA. To determine the positions and binding strength of proteins localized on DNA we have developed a combined magnetic and optical tweezers apparatus that allows for both sensitive and label-free detection. A DNA loop, that acts as a scanning probe, is created by looping an optically trapped DNA tether around a DNA molecule that is held with magnetic tweezers. Upon scanning the loop along the λ-DNA molecule, EcoRI proteins were detected with ~17 nm spatial resolution. An offset of 33 ± 5 nm for the detected protein positions was found between back and forwards scans, corresponding to the size of the DNA loop and in agreement with theoretical estimates. At higher applied stretching forces, the scanning loop was able to remove bound proteins from the DNA, showing that the method is in principle also capable of measuring the binding strength of proteins to DNA with a force resolution of 0.1 pN/[Formula: see text]. The use of magnetic tweezers in this assay allows the facile preparation of many single-molecule tethers, which can be scanned one after the other, while it also allows for direct control of the supercoiling state of the DNA molecule, making it uniquely suitable to address the effects of torque on protein-DNA interactions.http://europepmc.org/articles/PMC3670887?pdf=render
spellingShingle Marijn T J van Loenhout
Iwijn De Vlaminck
Benedetta Flebus
Johan F den Blanken
Ludovit P Zweifel
Koen M Hooning
Jacob W J Kerssemakers
Cees Dekker
Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.
PLoS ONE
title Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.
title_full Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.
title_fullStr Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.
title_full_unstemmed Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.
title_short Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.
title_sort scanning a dna molecule for bound proteins using hybrid magnetic and optical tweezers
url http://europepmc.org/articles/PMC3670887?pdf=render
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