A Horizontal Magnetic Tweezers for Studying Single DNA Molecules and DNA-Binding Proteins |
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| Authors: | Roberto Fabian Jr. Santosh Gaire Christopher Tyson Raghabendra Adhikari Ian Pegg Abhijit Sarkar |
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| Affiliation: | 1.Department of Physics and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA; (S.G.); (I.P.); (A.S.);2.Biomedical Engineering Department and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA;3.Department of Biology, The Catholic University of America, Washington, DC 20064, USA; |
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| Abstract: | We report data from single molecule studies on the interaction between single DNA molecules and core histones using custom-designed horizontal magnetic tweezers. The DNA-core histone complexes were formed using λ-DNA tethers, core histones, and NAP1 and were exposed to forces ranging from ~2 pN to ~74 pN. During the assembly events, we observed the length of the DNA decrease in approximate integer multiples of ~50 nm, suggesting the binding of the histone octamers to the DNA tether. During the mechanically induced disassembly events, we observed disruption lengths in approximate integer multiples of ~50 nm, suggesting the unbinding of one or more octamers from the DNA tether. We also observed histone octamer unbinding events at forces as low as ~2 pN. Our horizontal magnetic tweezers yielded high-resolution, low-noise data on force-mediated DNA-core histone assembly and disassembly processes. |
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| Keywords: | single molecule micromanipulation techniques horizontal magnetic tweezers DNA-histone interactions nucleosomes |
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