Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Melbourne, Australia
Pasteurella multocida is a Gram-negative bacterial pathogen classified into 16 serovars based on lipopolysaccharide (LPS) antigens. Previously, we have characterised the LPS outer core biosynthesis loci L1, L2, L3, L5 and L7, and have elucidated the full range of LPS structures associated with each. In this study, we have determined the LPS structures produced by the type strains representing the serovars 10, 11, 12 and 15 and characterized a new LPS outer core biosynthesis locus, L6, common to all. The L6 outer core biosynthesis locus shares significant synteny with the L3 locus but due to nucleotide divergence, gene duplication, and gene redundancy, the L6 and L3 LPS outer cores are structurally distinct. Using LPS structural and genetic differences identified in each L6 strain we have predicted a role for most of the L6 glycosyltransferases in LPS assembly. Importantly, we have identified two glycosyltransferases, GctD and GatB, that differ by one amino acid, A162T, but use different donor sugars (UDP-Glc and UDP-Gal respectively). The longest outer core oligosaccharide, produced by the serovar 12 type strain, contained a terminal region consisting of β-Gal-(1,4)-β-GlcNAc-(1,3)-β-Gal-(1,4)-β-Glc that was identical in structure to the vertebrate glycosphingolipid, paragloboside. Mimicry of host glycosphingolipids has been observed previously in P. multocida strains belonging to L3 LPS genotype, which produce LPS similar in structure to the globo-series of glycosphingolipids. The expression of a paragloboside-like oligosaccharide on the LPS produced by the serovar 12 type strain indicates that strains belonging to the L6 LPS genotype may also engage in molecular mimicry.
13C NMR, 1H NMR, GLC-MS, PCR, de-O-acylation, sugar analysis, DNA techniques, genetic methods, biochemical methods, CE-ESI-MS, bioinformatic analysis
NMR data for the completely deacylated LPS from Pasteurella multocida serovar 12 strain P1573
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6 C7
5,3,2 aXLDmanHepp 101.7 70.2 71.0 66.3 71.6 70.6 ?
5,3,3,0 xXEtN
5,3,3 P
5,3 aXLDmanHepp 100.3 80.5 75.9 67.2 73.3 70.0 64.4
5,4,6,6,4,3,4 bDGalp 103.2 71.3 72.7 68.6 75.5 62.4
5,4,6,6,4,3,2 Ac
5,4,6,6,4,3 bDGlcpN 101.6 57.2 72.1 79.4 76.5 61.1
5,4,6,6,4 bDGalp 104.0 71.6 83.2 69.9 76.9 62.4
5,4,6,6 bDGlcp 104.9 74.5 75.5 79.4 76.1 61.5
5,4,6 aXLDmanHepp 101.4 71.0 72.0 67.7 73.1 80.5 64.1
5,4 bDGlcp 104.8 74.9 78.4 70.9 75.2 66.2
5,6 aDGlcp 102.9 73.7 74.5 70.1 73.1 61.0
5 aXLDmanHepp 100.7 71.6 74.7 75.6 73.0 82.0 64.9
4,0,0 xXEtN
4,0 %xXP?
4 P
aXKdop
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6 H7
5,3,2 aXLDmanHepp 5.21 4.00 3.87 3.82 3.78 4.08 ?
5,3,3,0 xXEtN
5,3,3 P
5,3 aXLDmanHepp 5.75 4.32 4.46 4.08 3.67 4.08 3.61-3.72
5,4,6,6,4,3,4 bDGalp 4.47 3.54 3.67 3.93 3.74 3.74-3.79
5,4,6,6,4,3,2 Ac
5,4,6,6,4,3 bDGlcpN 5.02 3.18 3.87 3.78 3.65 3.88-3.96
5,4,6,6,4 bDGalp 4.52 3.72 3.90 4.20 3.74 3.74-3.79
5,4,6,6 bDGlcp 4.57 3.44 3.67 3.72 3.64 3.81-3.98
5,4,6 aXLDmanHepp 5.05 4.04 3.81 3.95 3.90 4.17 3.74-3.90
5,4 bDGlcp 4.59 3.52 3.40 3.61 3.49 3.72-4.07
5,6 aDGlcp 5.21 3.57 3.83 3.56 3.94 3.76-3.96
5 aXLDmanHepp 5.17 4.14 4.02 4.18 4.19 4.07 3.70
4,0,0 xXEtN
4,0 %xXP?
4 P
aXKdop
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6 C7/H7
5,3,2 aXLDmanHepp 101.7/5.21 70.2/4.00 71.0/3.87 66.3/3.82 71.6/3.78 70.6/4.08 ?/?
5,3,3,0 xXEtN
5,3,3 P
5,3 aXLDmanHepp 100.3/5.75 80.5/4.32 75.9/4.46 67.2/4.08 73.3/3.67 70.0/4.08 64.4/3.61-3.72
5,4,6,6,4,3,4 bDGalp 103.2/4.47 71.3/3.54 72.7/3.67 68.6/3.93 75.5/3.74 62.4/3.74-3.79
5,4,6,6,4,3,2 Ac
5,4,6,6,4,3 bDGlcpN 101.6/5.02 57.2/3.18 72.1/3.87 79.4/3.78 76.5/3.65 61.1/3.88-3.96
5,4,6,6,4 bDGalp 104.0/4.52 71.6/3.72 83.2/3.90 69.9/4.20 76.9/3.74 62.4/3.74-3.79
5,4,6,6 bDGlcp 104.9/4.57 74.5/3.44 75.5/3.67 79.4/3.72 76.1/3.64 61.5/3.81-3.98
5,4,6 aXLDmanHepp 101.4/5.05 71.0/4.04 72.0/3.81 67.7/3.95 73.1/3.90 80.5/4.17 64.1/3.74-3.90
5,4 bDGlcp 104.8/4.59 74.9/3.52 78.4/3.40 70.9/3.61 75.2/3.49 66.2/3.72-4.07
5,6 aDGlcp 102.9/5.21 73.7/3.57 74.5/3.83 70.1/3.56 73.1/3.94 61.0/3.76-3.96
5 aXLDmanHepp 100.7/5.17 71.6/4.14 74.7/4.02 75.6/4.18 73.0/4.19 82.0/4.07 64.9/3.70
4,0,0 xXEtN
4,0 %xXP?
4 P
aXKdop