Fig.1. Schematic molecular model of the inner and outer membranes of E. coli K-12. Colored ovals and rectangles represent sugar residues, as indicated, whereas circles represent polar headgroups of various lipids. (Red, ethanolamine-phosphate; purple, ethanolamine pyrophosphate; yellow, glycerol-phosphate; blue ovals, glucosamine units; gray ovals, N-acetylmuramic acid units). Abbreviations: Kdo, 3-deoxy-D-manno-octulosonic acid; LPS, lipopolysaccharide (1, 2).