p
                  3                                        10
                  I                                         I


         64              $2
         504            392

         36                4

         2216
                                                 7
          6



Figure 4-4. Two-dimensional electrophoresis of purified polyhedral organelles of S.
          enterica used for N-terminal sequencing. A purified polyhedral organelle
          preparation (230 [tg of protein) was subjected to 2D-IEF-SDS-PAGE, blotted
          onto an Immobilon P membrane and then stained with Sypro Ruby.
          Subsequent to photographing the membrane was stained with Coomassie Blue
          R-250 and the protein spots were excised and analyzed by N-terminal
          sequencing as described in the Materials and Methods section. Molecular
          masses in kilodaltons and the IEF pH is indicated at the left and top of the gel,
          respectively.