ISSN:
0006-3525
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The DNA helix-coil transition has been studied in the presence of high concentrations of manganese ions (about 10-3M), which corresponds to the conditions close to equal stability of the A+T and G+C pairs, at the ionic strengths of 10-1, 10-2, and 1.6 × 10-3M Na+. With the Mn2+ ion effect, the transition range is significantly reduced to not more than 0.2°C at 1.2 × 10-3M Mn2+ and 1.6 × 10-3M Na+. The melting curves display a sharp kink at the end of the helix-coil transition, which is interpreted as an indication of the second-order phase transition. It is shown that the melting curves obtained can be approximated by a simple analytical expression 1 - θ = exp[-a(tc - t)], where θ is the DNA helix fraction, tc is the phase transition temperature, and a is an empirical parameter characterizing the breadth of the melting range and responsible for the magnitude of a jump of the helicity derivative with respect to the temperature at the phase transition point.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/bip.1979.360180915
