Fig. 2.

β-Kdo–containing bacterial glycans and the gene clusters associated with their biosynthesis. Only those gene clusters encoding enzymes central to the experimental approach are shown; others are given in Fig. S1. The analysis is confined to examples with known gene clusters and unambiguous polysaccharide structures. For all structures except CPS of Burkholderia oklahomensis, O-acetylation and O-propionylation are nonstoichiometric. In multidomain proteins, the conserved domains identified using the NCBI Conserved Domain Search service are indicated. β-Kdo GTs are shown in green, other GTs are represented in blue, acyltransferases (AT) in yellow, nucleotide sugar precursor synthesis genes in pink, and PS export machinery genes in magenta. For the WbbB protein from R. terrigena, the percentage of amino acid identity/similarity is indicated. The organization of O-antigen biosynthesis gene cluster of K. pneumoniae O12 is identical to that of R. terrigena, with WbbB sharing 72% identity and 83% similarity.