Abstract
Electrophoretic heterogeneity in preparations of arabis mosaic virus (AMV) was due to differences in net surface charge among the sedimenting components. The bottom component migrated more rapidly than the top component in polyacrylamide gels and on cellulose acetate strips. When nucleic acid was removed from bottom component the nucleic acid-free protein shell showed sedimentation and electrophoretic properties similar to those of top component.