FIG. 2.

Glycerol gradient centrifugation of the 126K-183K complex. The S100 fraction from TMV-infected tobacco leaves was mixed with the molecular-size marker proteins as described in Materials and Methods and centrifuged on a 10 to 40% linear gradient of glycerol in Tris-MgCl₂-DTT buffer for 8 h at 45,000 rpm. Aliquots of the glycerol fractions were fractionated by SDS-PAGE. The gel was treated for Western blot analysis against the anti-M antibodies. The location of the marker proteins is shown by arrows: A, bovine liver catalase (240 kDa); B, E. coli RNA polymerase (450 kDa).