DNA Deformations near Charged Surfaces: Electron and Atomic Force Microscopy Views
| Autor: | Bernd Rieger, Frank G. A. Faas, Dmitry I. Cherny, L.J. van Vliet |
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| Rok vydání: | 2009 |
| Předmět: |
Models
Molecular Flexibility (anatomy) Static Electricity Biophysics Electron Bending Microscopy Atomic Force 010402 general chemistry 01 natural sciences 03 medical and health sciences chemistry.chemical_compound Microscopy Static electricity medicine Molecule Computer Simulation 030304 developmental biology 0303 health sciences Nucleic Acid Chemistry DNA Adhesion 0104 chemical sciences Microscopy Electron Crystallography medicine.anatomical_structure Models Chemical Chemical physics Nucleic Acid Conformation |
| Zdroj: | Biophysical Journal. 97(4):1148-1157 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/j.bpj.2009.06.015 |
| Popis: | DNA is a very important cell structural element, which determines the level of expression of genes by virtue of its interaction with regulatory proteins. We use electron (EM) and atomic force microscopy (AFM) to characterize the flexibility of double-stranded DNA ( approximately 150-950 nm long) close to a charged surface. Automated procedures for the extraction of DNA contours ( approximately 10-120 nm for EM data and approximately 10-300 nm for AFM data) combined with new statistical chain descriptors indicate a uniquely two-dimensional equilibration of the molecules on the substrate surface regardless of the procedure of molecule mounting. However, in contrast to AFM, the EM mounting leads to a noticeable decrease in DNA persistence length together with decreased kurtosis. Analysis of local bending on short length scales (down to 6 nm in the EM study) shows that DNA flexibility behaves as predicted by the wormlike chain model. We therefore argue that adhesion of DNA to a charged surface may lead to additional static bending (kinking) of approximately 5 degrees per dinucleotide step without impairing the dynamic behavior of the DNA backbone. Implications of this finding are discussed. |
| Databáze: | OpenAIRE |
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