Figure 2

Distribution of Kdo ₂ -lipid A biosynthetic enzymes across bacteria genomes. Maximum likelihood phylogenies were reconstructed based on concatenated six protein sequences (A) and 16S rRNA nucleotide sequences (B). Enzymes identified are color-coded as follows: LpxA (A, red), LpxC (C, red), LpxD (D, red), LpxH (H, red), LpxH2 (H2, yellow), LpxK (K, blue), WaaA (W, blue), LpxL (L, blue), LpxM (M, purple), and LpxP (P, light blue). White boxes indicate the absence of the corresponding enzymes. Bacteria that have none of the enzymes and only LpxK are marked with white and blue stars, respectively. Red arrowheads indicate the points inferred to be the emergence of the Kdo₂-lipid A biosynthetic pathway with the last four enzymes (LpxK-LpxM). Circles at internal nodes indicate bootstrap-supporting values as follows: black circles ≥ 95%, gray circles ≥ 85%, and white circles ≥ 75%. Proteobacteria and Gram-positive bacteria are shown with green and orange letters/lines, respectively. Bacterial classifications (phylum, and for Proteobacteria, class) are shown in parentheses using the following abbreviations. Ac: Acidobacteria, Ba: Bacteroidetes, Ch: Chlamydiae, Cn: Cyanobacteria, Cr: Chlorobi, Di: Dictyoglomi, Fu: Fusobacteria, Ni: Nitrospire, Pl: Planctomycetes, Sp: Spirochaetes, Ve: Verrucomicrobia, α: Alphaproteobacteria, β: Betaproteobacteria, δ: Deltaproteobacteria, ε: Epsilonproteobacteria, and γ: Gammaproteobacteria. Group-II Gammaproteobacteria, those that have all nine enzymes, are shown with *.