Volume 81, Number 6, March 2008
|Number of page(s)||5|
|Section||Interdisciplinary Physics and Related Areas of Science and Technology|
|Published online||25 February 2008|
Short-fragment Na-DNA dilute aqueous solutions: Fundamental length scales and screening
Institut za fiziku - HR-10001 Zagreb, Croatia
2 Rudjer Bošković Institute - HR-10001 Zagreb, Croatia
3 Laboratoire de Physique des Solides, Université Paris Sud - F-91405 Orsay, France
4 Department of Physics, University of Ljubljana - SI-1000 Ljubljana, Slovenia
5 J. Stefan Institute - SI-1000 Ljubljana, Slovenia
6 Laboratory of Physical and Structural Biology, NICHD, National Institutes of Health - Bethesda, MD 20892, USA
Corresponding author: firstname.lastname@example.org
Accepted: 28 January 2008
Dielectric spectroscopy is used to investigate fundamental length scales of 146 bp short-fragment (nucleosomal) dilute Na-DNA solutions. Two relaxation modes are detected: the high- and the low-frequency mode. Dependence of the corresponding length scales on the DNA and on the (uni-valent) salt concentration is studied in detail, being different from the case of long, genomic DNA, investigated before. In low-added-salt regime, the length scale of the high-frequency mode scales as the average separation between DNAs, though it is smaller in absolute magnitude, whereas the length scale of the low-frequency mode is equal to the contour length of DNA. These fundamental length scales in low-added-salt regime do not depend on whether DNA is in a double-stranded or single-stranded form. On the other hand, with increasing added salt, the characteristic length scale of the low-frequency mode diminishes at low DNA concentrations probably due to dynamical formation of denaturation bubbles and/or fraying in the vicinity of DNA denaturation threshold.
PACS: 87.15.H- – Dynamics of biomolecules / 82.39.Pj – Nucleic acids, DNA and RNA bases / 77.22.Gm – Dielectric loss and relaxation
© EPLA, 2008
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