Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Campylobacter jejuni [ICD11:
XN4Q5 
]
NCBI PubMed ID: 36943186Publication DOI: 10.1021/acs.biochem.3c00012Journal NLM ID: 0370623Publisher: American Chemical Society
Correspondence: F.M. Raushel <raushel
tamu.edu>
Institutions: Department of Chemistry, Texas A&M University, College Station, Texas 77845, United States
Campylobacter jejuni is the leading cause of food poisoning in the United States. Surrounding the exterior surface of this bacterium is a capsular polysaccharide (CPS) that helps protect the organism from the host immune system. The CPS is composed of a repeating sequence of common and unusual sugar residues, including relatively rare heptoses. In the HS:5 serotype, we identified four enzymes required for the biosynthesis of GDP-3,6-dideoxy-β-l-ribo-heptose. In the first step, GDP-d-glycero-α-d-manno-heptose is dehydrated to form GDP-6-deoxy-4-keto-α-d-lyxo-heptose. This product is then dehydrated by a pyridoxal phosphate-dependent C3-dehydratase to form GDP-3,6-dideoxy-4-keto-α-d-threo-heptose before being epimerized at C5 to generate GDP-3,6-dideoxy-4-keto-β-l-erythro-heptose. In the final step, a C4-reductase uses NADPH to convert this product to GDP-3,6-dideoxy-β-l-ribo-heptose. These results are at variance with the previous report of 3,6-dideoxy-d-ribo-heptose in the CPS from serotype HS:5 of C. jejuni. We also demonstrated that GDP-3,6-dideoxy-β-l-xylo-heptose is formed using the corresponding enzymes found in the gene cluster from serotype HS:11 of C. jejuni. The utilization of different C4-reductases from other serotypes of C. jejuni enabled the formation of GDP-3,6-dideoxy-α-d-arabino-heptose and GDP-3,6-dideoxy-α-d-lyxo-heptose.
biosynthesis, serotype, capsular polysaccharide, Campylobacter jejuni, 3, 6-dideoxy-heptose
Structure type: polymer chemical repeating unit
Location inside paper: Fig. 1, HS:19
Compound class: CPS
Contained glycoepitopes: IEDB_115136,IEDB_135813,IEDB_137340,IEDB_140630,IEDB_141807,IEDB_151527,IEDB_151531,IEDB_231709,IEDB_423153
Methods: 1H NMR, NMR-2D, kinetics assays, genetic methods, biochemical methods, enzyme assay, UV
Related record ID(s): 22237
NCBI Taxonomy refs (TaxIDs): 197
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There is only one chemically distinct structure:
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