title: Evidence for the absence of swelling of alfalfa mosaic virions.
abstract: The stability of the quaternary structure of bottom and top components of alfalfa mosaic virus (respectively AMV-B and AMV-Ta-t) in the pH range 5.5 to 7.8 and at ionic concentrations of 0.01 and 0.1 M has been investigated using small-angle X-ray scattering and photon correlation spectroscopy. The X-ray scattering curves show no significant changes over the angular range measured (to a resolution of 1 100 A (-1)) under the various solvent conditions; the radius of gyration of AMV-Ta-t is constant at 113 +/- 3 A and the cross-sectional radius of gyration of AMV-B constant at 69 +/- 2 A. The translational diffusion constants D(20m,w)(0) of AMV-B and AMV-Ta-t are also constant being, respectively, 1.09 (+/-0.01) x 10(-7) and 1.51(+/-0.02) x 10(-7) cm(2)/sec. The RNase sensitivities of AMV-B particles isolated at pH 6 or pH 7 were found to be similar. These results show that under a wide range of solvent conditions the gross morphology of AMV virions remains stable. Hence unlike a number of spherical plant viruses, AMV does not show the phenomenon of swelling.
authors.affiliation: University of Leiden, Department of Biochemistry, Wassenaarseiveg 64, 2333 AL Leiden, The Netherlands.
authors.forename: G T
authors.initials: GT
authors.lastname: Oostergetel
authors.forename: P C
authors.initials: PC
authors.lastname: Krijgsman
authors.forename: J E
authors.initials: JE
authors.lastname: Mellema
authors.forename: S
authors.initials: S
authors.lastname: Cusack
authors.forename: A
authors.initials: A
authors.lastname: Miller