Fig. 1

Different molecules of the OM in E. coli. The cell envelope of E. coli has two distinct membranes: the OM and the IM. Structurally, OM is composed of phospholipids in the periplasmic leaflet and LPS in the external leaflet. LPS contain Kdo₂-lipid A, core and O-antigen, and the latter two form the polysaccharide portion of LPS. The biosynthesis of sugar groups in polysaccharide of LPS are derived from glucose 6-phosphate, an intermediate of glycolysis. The polymerized CA is secreted into the surface of the OM in E. coli K-12. CA contains six sugar groups also derived from the intermediates of glucose metabolic pathways. The structural model of flagella and type I fimbriae exhibited on the membrane in E. coli K-12. The structure of flagella and type I fimbria are transmembrane anchored in the membrane with the flagellar filament and mycelium outside. The biosynthesis or function of LPS, CA, flagella and fimbria all need co-factors ATP