Thermal Fluctuation Spectroscopy of DNA Thermal Denaturation

Nagapriya, KS and Raychaudhuri, AK (2010) Thermal Fluctuation Spectroscopy of DNA Thermal Denaturation. In: Biophysical Journal, 99 (8). pp. 2666-2675.

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Abstract

We have developed the technique of thermal fluctuation spectroscopy to measure the thermal fluctuations in a system. This technique is particularly useful to study the denaturation dynamics of biomolecules like DNA. Here we present a study of the thermal fluctuations during the thermal denaturation (or melting) of double-stranded DNA. We find that the thermal denaturation of heteropolymeric DNA is accompanied by large, non-Gaussian thermal fluctuations. The thermal fluctuations show a two-peak structure as a function of temperature. Calculations of enthalpy exchanged show that the first peak comes from the denaturation of AT rich regions and the second peak from denaturation of GC rich regions. The large fluctuations are almost absent in homopolymeric DNA. We suggest that bubble formation and cooperative opening and closing dynamics of basepairs causes the additional fluctuation at the first peak and a large cooperative transition from a partially molten DNA to a completely denatured state causes the additional fluctuation at the second peak.

Item Type:	Journal Article
Publication:	Biophysical Journal
Publisher:	Biophysical Society
Additional Information:	Copyright of this article belongs to Biophysical Society
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	19 Nov 2010 11:10
Last Modified:	19 Nov 2010 11:10
URI:	http://eprints.iisc.ac.in/id/eprint/33849

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