THE STEPWISE CONFORMATIONAL CHANGE OF POLY(L-LYSINE) IN AQUEOUS SOLUTION OF SODIUM 1-OCTANESULFONATE

The circular dichroism spectrum of poly(L-lysine)(PLL) in aqueous 1-octanesulfonate solution was measured as a function of surfactant concentration at varying temperatures and the conformational phase diagram was constructed. At temperatures above 10°C, the increase in surfactant concentration causes PLL to change stepwise from coil to β-form and from β-form to helical conformation, Upon lowering temperature, the surfactant concentration range, where PLL assumes β-form, becomes narrower and eventually disappears at around 10°C.