All-or-none (or something in between) transition of DNAY. Hayashi
Physical Chemistry 1, Center for Chemistry and Chemical Engineering Lund University - P.O. Box 124, S-221 00 Lund, Sweden
received 20 April 2004; accepted in final form 29 September 2004
published online 20 October 2004
DNA compaction can be caused by multivalent ions as condensing agents. Both discontinuous (all-or-none) and continuous (pearl-necklace structure) transitions have been observed in experiments as the concentration of the condensing agent was increased. We have investigated the DNA transition by analytical calculations in the infinite-chain limit. A mechanism for pearl-necklace structures could be a combinatorial entropy term, which favours a mixture of globules and coils in a single chain. However, when a surface term is taken into account, it gives rise to a discontinuous transition. We also consider the role of surface charges on the globule.
61.25.Hq - Macromolecular and polymer solutions; polymer melts; swelling.
© EDP Sciences 2004