Statics and Dynamics of Condensed DNA within Phages and Globules

Abstract

Several controversial issues concerning the packing of linear DNA in bacteriophages and globules are discussed. Exact relations for the osmotic pressure, capsid pressure and loading force are derived in terms of the hole size inside phages under the assumption that the DNA globule has a uniform density. A new electrostatic model is introduced for computing the osmotic pressure of rodlike polyelectrolytes at very high concentrations. At intermediate packing, a reptation model is considered for DNA diffusing within a toroidal globule. Under tight packing conditions, a model of Coulomb sliding friction is proposed. A general discussion is given of our current understanding of the statics and dynamics of confined DNA in the context of to the following experiments: characterization of the liquid crystalline phases, X-ray scattering by phages, osmotic stress measurements, cyclization within globules and single-molecule determination ofthe loading forces.