Study of the DNA/ethidium bromide interactions on mica surface by atomic force microscope: Influence of the surface friction
Autor: | David Pastré, Alain Zozime, Olivier Piétrement, Eric Le Cam |
---|---|
Rok vydání: | 2004 |
Předmět: |
chemistry.chemical_classification
Chemistry Organic Chemistry Biophysics 02 engineering and technology General Medicine 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry 0104 chemical sciences Biomaterials stomatognathic diseases chemistry.chemical_compound Crystallography Adsorption Bromide Molecule A-DNA Mica Counterion 0210 nano-technology Ethidium bromide DNA |
Zdroj: | Biopolymers. 77:53-62 |
ISSN: | 0006-3525 |
DOI: | 10.1002/bip.20185 |
Popis: | The influence of mica surface on DNA/ethidium bromide interactions is investigated by atomic force microscopy (AFM). We describe the diffusion mechanism of a DNA molecule on a mica surface by using a simple analytical model. It appears that the DNA diffusion on a mica surface is limited by the surface friction due to the counterion correlations between the divalent counterions condensed on both mica and DNA surfaces. We also study the structural changes of linear DNA adsorbed on mica upon ethidium bromide binding by AFM. It turns out that linear DNA molecules adsorbed on a mica surface are unable to relieve the topological constraint upon ethidium bromide binding. In particular, strongly adsorbed molecules tend to be highly entangled, while loosely bound DNA molecules appear more extended with very few crossovers. Adsorbed DNA molecules cannot move freely on the surface because of the surface friction. Therefore, the topological constraint increases due to the ethidium bromide binding. Moreover, we show that ethidium bromide has a lower affinity for strongly bound molecules due to the topological constraint induced by the surface friction. |
Databáze: | OpenAIRE |
Externí odkaz: |