Andres D, Gohlke U, Broeker NK, Schulze S, Rabsch W, Heinemann U, Barbirz S, Seckler R An essential serotype recognition pocket on phage P22 tailspike protein forces Salmonella enterica serovar Paratyphi A O-antigen fragments to bind as non-solution conformers Glycobiology23(4) (2013)
486-494
Bacteriophage P22 recognizes O-antigen polysaccharides of Salmonella enterica subsp. enterica (S.) with its tailspike protein (TSP). In the serovars S. Typhimurium, S. Enteritidis, and S. Paratyphi A, the tetrasaccharide repeat units of the respective O-antigens consist of an identical main chain trisaccharide but different 3,6-dideoxyhexose substituents. Here, the epimers abequose, tyvelose, and paratose determine the specific serotype. P22TSP recognizes O-antigen octasaccharides in an extended binding site with a single 3,6-dideoxyhexose binding pocket. We have isolated S. Paratyphi A octasaccharides which were not available previously and determined the crystal structure of their complex with P22TSP. We discuss our data together with crystal structures of complexes with S. Typhimurium and S. Enteritidis octasaccharides determined earlier. Isothermal titration calorimetry (ITC) showed that S. Paratyphi A octasaccharide binds P22TSP less tightly, with a difference in binding free energy of approximately 7 kJ/mol at 20 degrees C compared to S. Typhimurium and S. Enteritidis octasaccharides. Individual protein-carbohydrate contacts were probed by amino acid replacements showing that the dideoxyhexose pocket contributes to binding of all three serotypes. However, S. Paratyphi A octasaccharides bind in a conformation with an energetically unfavorable varphi / psi glycosidic bond angle combination. By contrast, octasaccharides from the other serotypes bind as solution-like conformers. Two water molecules are conserved in all P22TSP complexes with octasaccharides of different serotypes. They line the dideoxyhexose binding pocket and force the S. Paratyphi A octasaccharides to bind as non-solution conformers. This emphasizes the role of solvent as part of carbohydrate binding sites.
Methods: crystallography, thermodynamics, statistical analysis, crystallization, surface plasmon resonance (SPR), ITC 3D data: 3D data
Related record ID(s): 29424, 29904 NCBI Taxonomy refs (TaxIDs):54388 Reference(s) to other database(s): GTC:G37642RX, GlycomeDB:27020 Show glycosyltransferases
Ravenscroft N, Cescutti P, Gavini M, Stefanetti G, Maclennan CA, Martin LB, Micoli F Structural analysis of the O-acetylated O-polysaccharide isolated from Salmonella paratyphi A and used for vaccine preparation Carbohydrate Research404 (2015)
108-116
The structure was elucidated in this paper NCBI PubMed ID:2566578 Publication DOI:10.1016/j.carres.2014.12.002 Journal NLM ID:0043535 Publisher: Elsevier Correspondence: francesca.micolinovartis.com Institutions: Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa, Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy, Department of Life Sciences, Blg. C11, Universita di Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
Salmonella paratyphi A is increasingly recognized as a common cause of enteric fever cases and there are no licensed vaccines against this infection. Antibodies directed against the O-polysaccharide of the lipopolysaccharide of Salmonella are protective and conjugation of the O-polysaccharide to a carrier protein represents a promising strategy for vaccine development. O-Acetylation of S. paratyphi A O-polysaccharide is considered important for the immunogenicity of S. paratyphi A conjugate vaccines. Here, as part of a programme to produce a bivalent conjugate vaccine against both S. typhi and S. paratyphi A diseases, we have fully elucidated the O-polysaccharide structure of S. paratyphi A by use of HPLC-SEC, HPAEC-PAD/CD, GLC, GLC-MS, 1D and 2D-NMR spectroscopy. In particular, chemical and NMR studies identified the presence of O-acetyl groups on C-2 and C-3 of rhamnose in the lipopolysaccharide repeating unit, at variance with previous reports of O-acetylation at a single position. Moreover HR-MAS NMR analysis performed directly on bacterial pellets from several strains of S. paratyphi A also showed O-acetylation on C-2 and C-3 of rhamnose, thus this pattern is common and not an artefact from O-polysaccharide purification. Conjugation of the O-polysaccharide to the carrier protein had little impact on O-acetylation and therefore should not adversely affect the immunogenicity of the vaccine.
O-polysaccharide, O-acetylation, bacterial polysaccharide structure, Salmonella paratyphi A
Ravenscroft N, Cescutti P, Gavini M, Stefanetti G, Maclennan CA, Martin LB, Micoli F Structural analysis of the O-acetylated O-polysaccharide isolated from Salmonella paratyphi A and used for vaccine preparation Carbohydrate Research404 (2015)
108-116
The structure was elucidated in this paper NCBI PubMed ID:2566578 Publication DOI:10.1016/j.carres.2014.12.002 Journal NLM ID:0043535 Publisher: Elsevier Correspondence: francesca.micolinovartis.com Institutions: Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa, Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy, Department of Life Sciences, Blg. C11, Universita di Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
Salmonella paratyphi A is increasingly recognized as a common cause of enteric fever cases and there are no licensed vaccines against this infection. Antibodies directed against the O-polysaccharide of the lipopolysaccharide of Salmonella are protective and conjugation of the O-polysaccharide to a carrier protein represents a promising strategy for vaccine development. O-Acetylation of S. paratyphi A O-polysaccharide is considered important for the immunogenicity of S. paratyphi A conjugate vaccines. Here, as part of a programme to produce a bivalent conjugate vaccine against both S. typhi and S. paratyphi A diseases, we have fully elucidated the O-polysaccharide structure of S. paratyphi A by use of HPLC-SEC, HPAEC-PAD/CD, GLC, GLC-MS, 1D and 2D-NMR spectroscopy. In particular, chemical and NMR studies identified the presence of O-acetyl groups on C-2 and C-3 of rhamnose in the lipopolysaccharide repeating unit, at variance with previous reports of O-acetylation at a single position. Moreover HR-MAS NMR analysis performed directly on bacterial pellets from several strains of S. paratyphi A also showed O-acetylation on C-2 and C-3 of rhamnose, thus this pattern is common and not an artefact from O-polysaccharide purification. Conjugation of the O-polysaccharide to the carrier protein had little impact on O-acetylation and therefore should not adversely affect the immunogenicity of the vaccine.
O-polysaccharide, O-acetylation, bacterial polysaccharide structure, Salmonella paratyphi A
Ravenscroft N, Cescutti P, Gavini M, Stefanetti G, Maclennan CA, Martin LB, Micoli F Structural analysis of the O-acetylated O-polysaccharide isolated from Salmonella paratyphi A and used for vaccine preparation Carbohydrate Research404 (2015)
108-116
The structure was elucidated in this paper NCBI PubMed ID:2566578 Publication DOI:10.1016/j.carres.2014.12.002 Journal NLM ID:0043535 Publisher: Elsevier Correspondence: francesca.micolinovartis.com Institutions: Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa, Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy, Department of Life Sciences, Blg. C11, Universita di Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
Salmonella paratyphi A is increasingly recognized as a common cause of enteric fever cases and there are no licensed vaccines against this infection. Antibodies directed against the O-polysaccharide of the lipopolysaccharide of Salmonella are protective and conjugation of the O-polysaccharide to a carrier protein represents a promising strategy for vaccine development. O-Acetylation of S. paratyphi A O-polysaccharide is considered important for the immunogenicity of S. paratyphi A conjugate vaccines. Here, as part of a programme to produce a bivalent conjugate vaccine against both S. typhi and S. paratyphi A diseases, we have fully elucidated the O-polysaccharide structure of S. paratyphi A by use of HPLC-SEC, HPAEC-PAD/CD, GLC, GLC-MS, 1D and 2D-NMR spectroscopy. In particular, chemical and NMR studies identified the presence of O-acetyl groups on C-2 and C-3 of rhamnose in the lipopolysaccharide repeating unit, at variance with previous reports of O-acetylation at a single position. Moreover HR-MAS NMR analysis performed directly on bacterial pellets from several strains of S. paratyphi A also showed O-acetylation on C-2 and C-3 of rhamnose, thus this pattern is common and not an artefact from O-polysaccharide purification. Conjugation of the O-polysaccharide to the carrier protein had little impact on O-acetylation and therefore should not adversely affect the immunogenicity of the vaccine.
O-polysaccharide, O-acetylation, bacterial polysaccharide structure, Salmonella paratyphi A
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(previously named: Salmonella paratyphi A)
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