Current Progress in the Structural and Biochemical Characterization of Proteins Involved in the Assembly of Lipopolysaccharide

Figure 6

Pseudomonas LpxH bound to the lipid X product. (a) Ribbon structure of PaLpxH bound to lipid X (PDB: 5B49) [50]. Lipid X carbons are colored grey, and protein carbons are colored tan. Mn²⁺ ions are colored purple. Spectrum coloring begins with blue at the N-terminus. (b) Residues involved in lipid X binding from (a). Metal coordination is shown in purple with the following distances in Ångstroms: from Mn301 to H10 Nε (2.3), to H197 Nε (2.3), to D8 Oδ1 (2.2), to D41 Oδ2 (2.3), to bridging water (2.3), and to adjacent water (2.2) and from Mn302 to D41 Oδ2 (2.2), to N79 Oδ (2.1), to H195 Nδ (2.3), to H114 Nε (2.2), and to bridging water (2.2). Hydrogen-bond and salt-bridge interactions are shown in pink with distances in Ångstroms of 2.7 from H195 O to bridging water, 2.9 from 2-acyl chain β-hydroxyl to R157 Nη1, 2.8 from glucosamine 4-hydroxyl to T164 Oγ and 2.9 to K167 Nζ, 3.3 from K167 Nζ to 3-acyl chain carbonyl and 2.8 to its β-hydroxyl, 2.8 from glucosamine 6-hydroxyl to H195 Nε, 2.8 from glucosamine 2-amino to S160 Oγ, and 2.7 from 1-phosphate to bridging water and 3.4 to adjacent water and 2.6 to N79 Nδ and 2.8 and 3.1, respectively, to R80 Nε and Nη2.