Purified preparations of tobacco necrosis virus (Nicotianavirus II)

Two nucleoproteins with similar chemical composition have been isolated from the leaves of tobacco plants infected with tobacco necrosis virus. One of these is crystalline and has a sedimentation constant of 130 × 10 −13 ; the other is amorphous and its principal component has a sedimentation constant of 58 × lO −13 . Each preparation will infect plants at a dilution of 1 in 108 and will precipitate specifically with antiserum at a dilution of 1 in 3·2 × 10 5 . The nature of the difference between preparations in the two states is obscure and it has not proved possible to convert the one into the other.