Cooperative B-Z transition of poly(dG-dC) induced by spermine at physiological temperature in aqueous medium

Spermine induced B-Z transition of poly(dG-dC) in aqueous medium at and above physiological temperature, at cellular concentration levels in low ionic strength medium. The amine to phosphate ratio, A/P, at the midpoint of the transition decreases with increase in temperature. The enthalpy change was 45 +/- 8 kcal per mol of cooperative unit; the transition induced by spermine is highly cooperative with a cooperative unit length of 700 +/- 20 at 50 degrees C.