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  • Aggregated DNA in ethanol solution
    Piškur, Jure, 1960-2014 ;
    A recently developed mechanochemical method has provided a new, efficient toolfor studies on the thermal stability and structure of aggregated DNA in ethanol-water solutions. At low ethanol ... concentrations DNA is fully soluble and is in the B form. However, with increasing ethanol concentration the melting temperature of DNA, Tm, decreases. At a critical ethanol concentration, dependent on the nature and concentration of the counterion, aggregation of the DNA molecules sets in. This is reflected in a marked increase in Tm indicating that the aggregated DNA molecules are thermally morestable than the dissolved ones. However, they are still in the B form. In general, Tm of aggregated DNA also decreases with further increasing ethanol concentration and is dependent on the nature of the counterion, but Tm is not affected by the concentration of the counterion (excess salt) in the ethanol-water solution. When the ethanol concentration reaches the range of 70-80% (v/v), the B-to-A conformational transition occurs in the case of Na-, K- and CsDNA. Above this transition point the A form is more stable than the Bform due to the reduced water activity and to increased interhelical interactions. At very high ethanol concentrations, above 85% and dependent on the nature of the counterion, a drastic change in the thermal behaviour is observed. Apparently such a strong interhelical interaction is induced in theaggregated DNA that the DNA is stabilized and cannot adopt a random coil state even at very high temperatures. This stability of DNA in the P form is fully reversed if the ethanol concentration is lowered and the activity of water, thereby, is restored.
    Vir: FEBS letters. - ISSN 0014-5793 (Letn. 375, št. 3, 1995, str. 174-178)
    Vrsta gradiva - članek, sestavni del
    Leto - 1995
    Jezik - angleški
    COBISS.SI-ID - 25493209

vir: FEBS letters. - ISSN 0014-5793 (Letn. 375, št. 3, 1995, str. 174-178)
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