FIG. 1.

Phosphatidylcholine and phosphorylcholine biosynthetic pathways showing biosynthetic genes and intermediates. The three described pathways are the lic-1 pathway (in grey), found in commensal Neisseria and H. influenzae (33, 43)—previous work showed that there are no homologues of this pathway in pathogenic Neisseria (32, 33); the pmtA pathway, found in Pseudomonas, Bradyrhizobium, Rhodobacter, and Sinorhizobium (4, 8, 19, 47); and the pcs pathway, found in Sinorhizobium and Pseudomonas (8, 47). Genes and proteins identified and characterized in this study are marked by asterisks. LOS, lipooligosaccharide.