FIGURE 1.

Proposed model for pEtN modifications catalyzed by EptC. The model illustrates the bifunctional nature of EptC in the periplasmic modification of lipid A and the flagellar rod component FlgG of C. jejuni with pEtN. C. jejuni lipid A is shown as a disaccharide of 2,3-diamino-2,3-dideoxy-d-gluopyranose that is hexa-acylated and bis-phosphorylated. Phosphoethanolamine modification of Campylobacter lipid A occurs on the phosphate groups (7) and modification of FlgG occurs on threonine 75. The model indicates that phosphatidylethanolamine serves as the pEtN donor, resulting in the production of diacylglycerol, which can be recycled for phospholipid synthesis.