Fig. 8: Transport of LPS across the cell envelope.

Shown are representations of MsbA, which mediates the transport of core-lipid A across the IM, and the Lpt complex (LptB₂FGCADE), which mediates LPS extraction from the IM and its transport through the periplasm and OM. As described in the text, the O antigen can be synthesized on Und-P and transported across the IM by different pathways (Fig. 5). If made, the O antigen is ligated to core-lipid A in the periplasmic leaflet of the IM by WaaL (not shown).