TraC associates with the membranes in strains carrying a functional pKM101 transfer machinery. Lanes represent Western blot analysis with TraC-specific antiserum after SDS-PAGE of subcellular fractions from strain FM433 without plasmid (−) or carrying pKM101 (101) or derivatives with transposon insertions in genes encoding TraM (M), TraB (B), TraC (C), Eex (Ex), TraD (D), or TraE (E). Arrows indicate membrane-associated TraC.