Evidence for Direct Binding of the First Component of Complement, C1, to Outer Membrane Proteins from Salmonella minnesota

The outer membrane of gram-negative bacteria consists of a tight lattice of lipopolysaccharides (LPS), phospholipids, and proteins. It has been shown in E. coli and S. typhimurium that LPS molecules are exclusively localized in the outer layer of the outer membrane (Muhlradt and Golecki 1975; Smit et al. 1975; Funatura and Nikaido 1980). Localization of proteins in the outer membrane is also indicated by the fact that various major outer membrane proteins in association with LPS, serve as receptors for phages (Datta et al. 1977; Mu-TOH et al. 1978; Henning and Jann 1979; Yu and Mizushima 1982) and colicins (Kadner et al. 1979; Konisky 1979).