Fig. 2. Interaction of purified full-length SpoIIE or purified SpoIIE (II–III) with SpoIIE and FtsZ from sporulating cell extracts. Cell extract was incubated with strep-tagged protein on magnetic beads and washed. Proteins from the beads were separated by SDS–PAGE and (A) silver stained or blotted (B) with anti-SpoIIE antibodies and (C) with anti-FtsZ antibodies. Lane 1, total cell extract; lane 2, cell extract incubated with purified strep-tagged SpoIIE (II–III); lane 3, cell extract incubated with purified strep-tagged full-length SpoIIE; lane 4, cell extract incubated with purified strep-tagged Mbl. In (A), the arrowhead for each lane points to the protein that is bound to the magnetic beads. Strep-tagged proteins are referred as to ^TSpoIIE, ^TSpoIIE (II–III) and ^TMbl. In (B) and (C), the positions of full-length SpoIIE, SpoIIE (II–III) and FtsZ are indicated by arrows. M, Biolabs broad range marker. The sizes of the proteins (in kilodaltons) are indicated on the left side of the figure.