(A) A central section of a tomogram showing S. Typhimurium minicell containing multiple injectisomes. (B–D) Central sections of sub-tomogram averages showing injectisomes of WT, ΔsipB, and ΔsipD, respectively. (E) A schematic of the injectisome. Outer membrane (OM), peptidoglycan (PG), sorting platform, and inner membrane (IM) of S. Typhimurium are annotated. (F–H) Central sections of tomograms showing injectisomes from strains expressing epitope-tagged (FLAG) SipB, SipC, and SipD, respectively. Yellow arrow indicates antibody bound to the epitope-tag.