Bordetella wlbK gene product domains involved in bacterial polysaccharide synthesis, and similar domainsThis model includes gene wlbJ (also known as bplJ, bplK, wlbjK) product protein, one of 12 genes that is involved in liposaccharide (LPS) synthesis. The liposaccharides (LPS) of Bordetella species are pyrogenic, mitogenic, and toxic, and can activate and induce tumor necrosis factor production in macrophages, similar to endotoxins from other gram-negative bacteria. Also, while the family Enterobacteriaceae expresses smooth-type LPS, the Bordetella LPS molecules differ in chemical structure; B. bronchiseptica and B. parapertussis synthesize a long-chain polysaccharide consisting of a homopolymer of 2,3-dideoxy-2,3-diN-acetylgalactosaminuronic acid (2,3-diNAcGalA), known as O antigen, whereas B. pertussis does not and is therefore more similar to rough-type LPS. This substantial structural difference between the LPS molecules of the three main pathogenic bordetellae likely confers quite different surface properties on the different species. Gene characterization studies show that wlbJ and wlbK are two apparently separate genes in B. pertussis, but are fused into a single open reading frame in B. bronchiseptica and B. parapertussishu. Studies show that mutations in wlbJK do not affect LPS biosynthesis but their function remains unclear.