Regensburg 2016 – scientific programme
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BP: Fachverband Biologische Physik
BP 24: Posters - Single Molecule Biophysics
BP 24.6: Poster
Monday, March 7, 2016, 17:30–19:30, Poster C
Splitting of plasmid ds-DNA on ultrathin films of alkylamines on graphite — •Caroline Falk1, Nikolai Severin1, Lei Tang2, Stefan Zauscher2, and Jürgen P. Rabe1 — 1Department of Physics & IRIS Adlershof, Humboldt-Universität zu Berlin — 2Mechanical Engineering and Materials Science, Duke University
DNA replication is an important process in the human body. Replication of double-stranded (ds)-DNA requires unwinding of the helical structure and local melting of ds-DNA into two single strands [1]. The exact mechanism of the initial melting is still unknown. DNA, when stretched in solution, overwinds and melts [2]. This was argued to give insight onto the replication mechanism. It is difficult, however, to access the direct conformational changes during stretching in solution. Recent work demonstrated that this transition can be imaged with scanning force microscopy on a graphite surface coated with an alkylamine layer [3]. ds-DNA can be controlled by an amphiphilic layer, since the DNA conformation depends on the amphiphile concentration. In particular we analyzed different DNA lengths on the same surface, and we found that at a specific concentration of octadecylamine the ds-DNA plasmid ring splits into two single strands at one position. The splitting can be analyzed as a function of total plasmid length, ultrathin amphiphilic film and base pairs.
1. D.Coman, I.M.Russu, Journal of Biological Chemistry 280, 20216 (2005). 2. J.Adamcik, S.Tobenas, G.Di Santo, D.Klinov, G.Dietler, Langmuir, 25, 3159 (2009). 3. H.Liang, N. Severin, W.Zhuang, J.P.Rabe, submitted.