Binding of proflavine and ethidium bromide to two forms of T2 bacteriophage with different sedimentation coefficients

Abstract

Equilibrium and kinetic studies of binding of proflavine and ethidium bromide to T2 phage indicate that (1) most of the intraphage DNA is accessible to proflavine; (2) the bulkier ethidium cation binds to a limited amount of DNA within the phage head; (3) intraphage DNA and free DNA in solutions of high ionic strength have similar equilibrium constants for binding to proflavine and ethidium; (4) on a time scale of minutes to hours, there is little difference in the permeabilities of the fast sedimenting (1000 S) and slow sedimenting (700S) forms of T2 phage as measured by proflavine binding.