Equilibrium Sedimentation of Turnip Yellow Mosaic Virus

Autor: W. Godschalk, D. W. Kupke, Jesse W. Beams, J. H. McGee
Rok vydání: 1974
Předmět:
Zdroj: Proceedings of the National Academy of Sciences. 71:3866-3868
ISSN: 1091-6490
0027-8424
DOI: 10.1073/pnas.71.10.3866
Popis: Sedimentation equilibrium was achieved with turnip yellow mosaic virus at low speeds (600 rpm) in a magnetic ultracentrifuge. The experiments were carried out in the newly installed constant-speed rotor, equipped with automatic control and an electromagnetic drive. A particle mass of 5.55 × 10 6 daltons was calculated for the virus at vanishing concentrations, in essential agreement with the earlier results using the more tedious procedure with a freely coasting rotor. In order to interpret the observed departure from ideal behavior (nonassociating conditions), preferential interaction experiments were carried out by magnetic densimetry. These showed that a strong Donnan effect exists at pH 7, which contributed > 10 3 times more to the nonideality than did the excluded volume effect. A net negative charge of about 3.5 × 10 3 per particle was estimated at this pH.
Databáze: OpenAIRE