Document Type
Article
Publication Date
11-2008
Department 1
Physics
Abstract
We have investigated the energetics of DNA condensation by multivalent polyamine cations. Solution small angle x-ray scattering was used to monitor interactions between short 25 base pair dsDNA strands in the free supernatant DNA phase that coexists with the condensed DNA phase. Interestingly, when tetravalent spermine is used, significant inter-DNA repulsion is observed in the free phase, in contrast with the presumed inter-DNA attraction in the coexisting condensed phase. DNA condensation thus appears to be a discrete, first-order-like, transition from a repulsive gaseous to an attractive condensed solid phase, in accord with the reported all-or-none condensation of giant DNA. We further quantify the electrostatic repulsive potentials in the free DNA phase and estimate the number of additional spermine cations that bind to DNA upon condensation.
Copyright Note
This is the publisher's version of the work. This publication appears in Gettysburg College's institutional repository by permission of the copyright owner for personal use, not for redistribution.
Recommended Citation
Qiu X., Andresen K., Lamb J.S., Kwok L.W., & Pollack, L. (2008). Abrupt transition from a free, repulsive to a condensed, attractive DNA phase, induced by multivalent polyamine cations. Physical Review Letters, 101(228101). http://dx.doi.org/10.1103/PhysRevLett.101.228101
Required Publisher's Statement
Copyright © 2008, The American Physical Society