FIGURE 7.

Proposed pathway of V. cholerae inner core biosynthesis and secondary acylation of lipid A. The V. cholerae WaaA transfers a single Kdo moiety to the 6′-position of V. cholerae lipid IV_A (Fig. 2A). Vc0227, the V. cholerae KdkA, catalyzes the addition of a phosphate group to the Kdo sugar (Fig. 2B). Vc0213 then adds an acyl chain to the 2′-position, using either C14:0-ACP or C14:0-CoA as an acyl donor (Figs. 5 and 6). Additional lipid A modifying enzymes and late acyltransferases are necessary to generate the hexa-acylated lipid A structure of V. cholerae O1 previously reviewed by Chatterjee and Chaudhuri (11).