Denaturation and renaturation of viral ribonucleic acd. II. Characterization of the products resulting from annealing R17 ribonucleic acid with denatured replicative form or with denatured replicative intermediate.

The ribonucleic acid (RNA) product resulting from annealing R17 RNA with denatured replicative form or replicative intermediate could be divided into two distinct types of RNA by precipitation in 1.5 m NaCl. The RNA found in the salt supernatant fluid was resistant to digestion by ribonuclease, had a sedimentation coefficient of 15S, and displayed a sharp thermal transition. The RNA in the salt supernatant fluid appeared to be identical to replicative form. The RNA found in the salt precipitate was resistant to digestion by ribonuclease, but possessed both single- and double-stranded characteristics. The RNA sedimented as a broad band in a sucrose gradient, with a sedimentation coefficient of 15S, and displayed a melting transition characteristic of a mixture of single- and double-stranded RNA. Mild ribonuclease digestion of the salt-precipitable RNA produced a ribonuclease-resistant material with sedimentation properties identical to the RNA found in the salt supernatant fluid.