Biosynthesis of GDP-d-glycero-α-d-manno-heptose for the Capsular Polysaccharide of Campylobacter jejuni

Abstract

The capsular polysaccharide (CPS) structure of Campylobacter jejuni contributes to its robust fitness. Many strains contain heptose moieties in their CPS units. The precursor heptose is GDP-d-glycero-α-d-manno-heptose; modifications to the stereochemistry at C3–C6 as well as additions of methyl and phosphoramidate groups lend to the hypervariability of the C. jejuni CPS structures. Synthesis of GDP-d-glycero-α-d-manno-heptose has been described previously, but using enzymes from Aneurinibacillus thermoaerophilus DSM 10155. Here we describe the complete synthesis of GDP-d-glycero-α-d-manno-heptose using enzymes from C. jejuni NTCC 11168: Cj1152 and Cj1423–Cj1425. Our results yield kinetic parameters for these enzymes and outline a successful strategy for milligram–gram scale synthesis of GDP-d-glycero-α-d-manno-heptose. This achievement is critical for the characterization of other carbohydrate tailoring enzymes, which are expected to utilize GDP-d-glycero-α-d-manno-heptose for the biosynthesis of more complex carbohydrates in the CPS of C. jejuni.

Virus-Host Interactions Reveal Potential Roles Towards Phosphorus Cycling in South Atlantic Ocean Euphotic Zones

“…These were dereplicated to 104 high and medium quality MAGs (>50% completeness and <10% contamination) following the MIMAG reporting standards [54]. In this study, we were able to retrieve a disproportionate number of high (32) and medium (72) draft quality MAGs compared to a recent study conducted in the SAO [52] (Supplementary Table 2). These MAGs represent the largest compendium of SAO genomes and comprised of taxonomically diverse archaeal (2) and bacterial (8) phyla (Fig.…”

“…Of these genes, three had functional assignments to a liated sequences previously recovered from unclassi ed Phycodnaviridae which are known to infect algae in the Pyramimonas order [71]. gmhB catalyses two pathways that result in the production of precursors for the S-layer glycoprotein and Lipid A biosynthesis [70,72]. Previous studies have shown that microbial communities in low phosphorus environments use alternative P-recycling mechanisms [43,73].…”

ADP‐heptose enables Helicobacter pylori to exploit macrophages as a survival niche by suppressing antigen‐presenting HLA‐II expression

“…ADP-heptose and other heptose metabolites are essential intermediates of the lipopolysaccharide heptose core biosynthetic pathway in all Gram-negative bacteria [12,14,[20][21][22][23] and can also be incorporated into bacterial surface layers [24,25] or produced by some Gram-positive bacteria [26]. Therefore, our results strongly suggest that the mechanism of adaptive immune response modulation and effects on antigen presentation based on this specific MAMP might also be adopted by other pathogenic bacteria.…”

Functional Characterization of Two PLP-Dependent Enzymes Involved in Capsular Polysaccharide Biosynthesis from Campylobacter jejuni

“…jejuni NCTC 11168 is composed of 35 genes, as illustrated in Figure S1 . Previous investigations have functionally characterized the genes necessary for the biosynthesis of the d -glycero- l -gluco-heptose moiety and modification (Cj1152, Cj1423, Cj1424, Cj1425, Cj1427, Cj1428, and Cj1430). − In addition, the enzymes Cj1415, Cj1416, Cj1417, and Cj1418 have been shown to be required for the biosynthesis of the phosphoramidate modification, and gene knockout experiments have identified the enzymes (Cj1422 and Cj1421) required for the transfer of the phosphoramidate modifications to specific sugar receptors. ,− More recently, we have shown that Cj1441 is required for the conversion of uridine diphosphate (UDP)-glucose to UDP-glucuronate and that this enzyme is unable to catalyze the formation of an amide bond via the attack of an amine substrate with the putative thioester intermediate formed during the oxidation of UDP-glucose . The enzymes required for the biosynthesis of the two amines (serinol and ethanolamine) found in the HS:2 capsule are currently unknown.…”