Naslov
Dielectric relaxation of aqueous DNA

Autori
Vuletić, Tomislav ; Tomić, Silvia ; Dolanski Babić, Sanja ; Ivek, Tomislav ; Krča, Sanja ; Griparić, Lorena ; Podgornik, Rudi

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Abstract book of 6th International Conference of Bilogical Physics / Grigera, J.Raul - Montevideo : Imprenta Gega, 2007, 63-63

ISBN
978-9974-8002-2-9

Skup
6th International Conference of Biological Physics

Mjesto i datum
Montevideo, Urugvaj, 27.08.2007. - 31.08.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
dielectric relaxation ; DNA ; fundamental length scales ; polyelectrolytes

Sažetak
Detailed spectroscopic (40 Hz - 110 MHz) study of complex dielectric function of aqueous solutions of native (genomic) DNA molecules will be presented. A study was performed for a rather broad range of added salt, 0.01 – 5 mM and DNA concentrations, 0.01 – 10 mg/mL (semi-dilute solutions). For the first time with a single setup (developed in our laboratory) two broad relaxation modes were observed, low (LF) and high (HF) frequency ones, in kHz and MHz ranges, respectively [1]. The corresponding relaxation times τ were related to the length scales L, via simple diffusion relation L2~Dτ . The observed length scales were identified with different length scales previously described in theories of polymers and polyelectrolytes. This provided lacking experimental insight in the behavior of DNA as a polyelectrolyte. The dielectric strength of the modes [1], when rescaled by the respective length scale and DNA concentrations, provided further insight by allowing us to argue that the free DNA counterions are primarily active in the HF relaxation, while the condensed counterions play a role only in the LF relaxation. Finally, we put our results in perspective regarding the integrity of the double stranded form of DNA at low salt conditions. That is, we have come to the conclusion that unzipping of DNA in the denaturing environment of low salt is probably at most local and complete separation of the strands at semi-dilute solutions is never really accomplished. We plan to address this further. *Also at Laboratory of Physical and Structural Biology NICHD, National Institutes of Health, Bethesda, MD, USA [1] S.Tomic, T.Vuletic, S.Dolanski Babic, S.Krca, D.Ivankovic, L.Griparic, R.Podgornik, Phys.Rev.Lett. 2006, 97, 098303 ; Phys.Rev.E 2007, 75, 021905.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Drvna tehnologija

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