Stabilization of DNA-Polycation Complex by Lithium Perchlorate

Abstract

The polycation forms a complex with DNA. The complex was stabilized to thermal denaturation by millimolar concentrations of LiClO4, in the range of 0.1-0.10 M LiClO4. No hyperchromicity was observed in the thermal profiles, and instead, hyperchromicity was observed. The complex showed no significant extrinsic CD band, but showed LiClO4-dependent alterations in the DNA intrinsic bands. It was found that Li+ was primarily responsible for the stabilization of the complex. It is proposed that Li+ stabilization arises through ternary complex formation and that the chaotropic ClO4- catalyzes conversion of less stable DNA-polycation complex into a more stable form. © 1987.