NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers.
While many proteins are involved in the assembly and (re)positioning of nucleosomes, the dynamics of protein-assisted nucleosome formation are not well understood. We study NAP1 (nucleosome assembly protein 1) assisted nucleosome formation at the single-molecule level using magnetic tweezers. This m...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2012-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3457989?pdf=render |
| _version_ | 1818133739243307008 |
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| author | Rifka Vlijm Jeremy S J Smitshuijzen Alexandra Lusser Cees Dekker |
| author_facet | Rifka Vlijm Jeremy S J Smitshuijzen Alexandra Lusser Cees Dekker |
| author_sort | Rifka Vlijm |
| collection | DOAJ |
| description | While many proteins are involved in the assembly and (re)positioning of nucleosomes, the dynamics of protein-assisted nucleosome formation are not well understood. We study NAP1 (nucleosome assembly protein 1) assisted nucleosome formation at the single-molecule level using magnetic tweezers. This method allows to apply a well-defined stretching force and supercoiling density to a single DNA molecule, and to study in real time the change in linking number, stiffness and length of the DNA during nucleosome formation. We observe a decrease in end-to-end length when NAP1 and core histones (CH) are added to the dsDNA. We characterize the formation of complete nucleosomes by measuring the change in linking number of DNA, which is induced by the NAP1-assisted nucleosome assembly, and which does not occur for non-nucleosomal bound histones H3 and H4. By rotating the magnets, the supercoils formed upon nucleosome assembly are removed and the number of assembled nucleosomes can be counted. We find that the compaction of DNA at low force is about 56 nm per assembled nucleosome. The number of compaction steps and associated change in linking number indicate that NAP1-assisted nucleosome assembly is a two-step process. |
| first_indexed | 2024-12-11T08:57:30Z |
| format | Article |
| id | doaj.art-880d8e6fe41b41c594b7ab9ab87200b6 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-11T08:57:30Z |
| publishDate | 2012-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-880d8e6fe41b41c594b7ab9ab87200b62022-12-22T01:13:50ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0179e4630610.1371/journal.pone.0046306NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers.Rifka VlijmJeremy S J SmitshuijzenAlexandra LusserCees DekkerWhile many proteins are involved in the assembly and (re)positioning of nucleosomes, the dynamics of protein-assisted nucleosome formation are not well understood. We study NAP1 (nucleosome assembly protein 1) assisted nucleosome formation at the single-molecule level using magnetic tweezers. This method allows to apply a well-defined stretching force and supercoiling density to a single DNA molecule, and to study in real time the change in linking number, stiffness and length of the DNA during nucleosome formation. We observe a decrease in end-to-end length when NAP1 and core histones (CH) are added to the dsDNA. We characterize the formation of complete nucleosomes by measuring the change in linking number of DNA, which is induced by the NAP1-assisted nucleosome assembly, and which does not occur for non-nucleosomal bound histones H3 and H4. By rotating the magnets, the supercoils formed upon nucleosome assembly are removed and the number of assembled nucleosomes can be counted. We find that the compaction of DNA at low force is about 56 nm per assembled nucleosome. The number of compaction steps and associated change in linking number indicate that NAP1-assisted nucleosome assembly is a two-step process.http://europepmc.org/articles/PMC3457989?pdf=render |
| spellingShingle | Rifka Vlijm Jeremy S J Smitshuijzen Alexandra Lusser Cees Dekker NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers. PLoS ONE |
| title | NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers. |
| title_full | NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers. |
| title_fullStr | NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers. |
| title_full_unstemmed | NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers. |
| title_short | NAP1-assisted nucleosome assembly on DNA measured in real time by single-molecule magnetic tweezers. |
| title_sort | nap1 assisted nucleosome assembly on dna measured in real time by single molecule magnetic tweezers |
| url | http://europepmc.org/articles/PMC3457989?pdf=render |
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