Unusual biphasic melting behaviour of Rhodotorula gracilis DNA.

Vishnuvardhan, D. and Divakar, S. and Joseph, R. (1995) Unusual biphasic melting behaviour of Rhodotorula gracilis DNA. Biochemical and Biophysical Research Communications, 211 (3). pp. 978-85. ISSN 0006-291X

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Abstract

Ultraviolet, fluorescence and CD spectral analysis suggested unusual structural features of Rhodotorula gracilis ATCC 90950 DNA. R. gracilis DNA exhibited 13% hyperchromicity at 260 nm as against 26% shown by calf thymus DNA. The biphasic melting curve, one phase between 88-92 degrees C and the other between 92-97 degrees C, was attributed to different unwinding pattern of R. gracilis DNA as a function of rise in temperature. The binding affinity of ethidium bromide to R. gracilis DNA determined was almost the same as that of calf thymus DNA. Fluorescence spectra with rise in temperature showed decrease in the quanta of fluorescence intensity after transition temperature, suggesting the quenching due to variation in structure. The CD spectra of R. gracilis DNA did not resemble the spectra of any of the known DNA forms and it showed increase in the magnitude of negative band with rise in temperature suggesting a B-C transition. Disruption of intermolecular and higher order structures by sonication and salt concentration did not change this behaviour implicating the influence of sequence and base composition of R. gracilis DNA on thermal melting transition.

Item Type:	Article
Uncontrolled Keywords:	R. gracilis, uv spectra
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 03 Biochemistry & Molecular Biology
Divisions:	Food Microbiology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	09 Mar 2012 09:44
Last Modified:	01 Oct 2018 09:35
URI:	http://ir.cftri.res.in/id/eprint/2249

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