[Liberation of DNA from particles of CD phage of DNA-protein complex: Properties of DNA in the complex and the effect of formaldehyde on the complex structure]

Abstract

Properties of DNA in a complex with protein, which was liberated after destruction of CD phage by heat treatment in solutions with low ionic strength, were studied. DNA in the complex did not differ from free DNA under the same conditions as shown by spectra of circular dichroism and by the type of melting during the thermic denaturation. As demonstrated by viscosimetry and gradient centrifugation in cesium sulfate, 1.5% formaldehyde inhibited the dissociation of the complex studied in a medium containing 0.15 M NaCl. In the medium with 1.5% of HCHO T degrees ml of DNA in the complex was distinctly higher than T degrees ml of free DNA under the same conditions. Electron microscopy showed that the complex studied comprised DNA ;molecules, associated with protein membrane in one or several internal sites.