ABSTRACT
DNA in solution can be condensed into dense aggregates by multivalent counterions. Here we investigate the effect of a nearby surface on the morphology of DNA condensates. We show that, contrary to what has often been assumed, interactions between DNA condensates and the surface can strongly influence the observed morphology. This limits the usefulness of surface probes such as atomic force microscopy for studying the morphology of condensates in bulk solution. Surprisingly, we find that the most negatively charged surface disturbs the condensate morphology most, suggesting that the microscopic mechanism resulting in DNA condensation is also responsible for the attractive force between DNA and the surface.
Subject(s)
Bacteriophage lambda/chemistry , DNA, Viral/chemistry , Spermidine/chemistry , Ions , Microscopy, Atomic ForceABSTRACT
Nuclear-spin relaxation rates resulting from shape fluctuations of unilamellar quasispherical vesicles are calculated. We show that in the kHz range these fluctuations yield-in contrast to previous conclusions on planar membranes - a relaxation rate proportional to the inverse Larmor frequency and provide direct information on the bending rigidity of membranes.
