Negative staining TEM analysis of large unilamellar vesicle–bound VCC. (A) Protomer of VCC crystal structure (PDB accession no. 1XEZ) shows the five prominent domains of the toxin. (B) Crystal structure of detergent-solubilized VCC heptamer (PDB accession no. 3O44) represented on a cartoon membrane. A single protomer of VCC is denoted by the colored ribbons in the side and top views of the structure. (C) A representative negative staining micrograph shows the uniform distribution of VCC in lipid vesicles. The red boxed area has been enlarged to show the liposomes studded with oligomeric toxin complexes. (D) Reference-free 2D class averages show top views and membrane-embedded side views of the protein. Scale bar = 100 Å. TM, transmembrane.