Science and Research

Structure of the Lipopolysaccharide from the Bradyrhizobium sp. ORS285 rfaL Mutant Strain

The importance of the outer membrane and of its main constituent, lipopolysaccharide, in the symbiosis between rhizobia and leguminous host plants has been well studied. Here, the first complete structural characterization of the entire lipopolysaccharide from an O-chain-deficient Bradyrhizobium ORS285 rfaL mutant is achieved by a combination of chemical analysis, NMR spectroscopy, MALDI MS and MS/MS. The lipid A structure is shown to be consistent with previously reported Bradyrhizobium lipid A, that is, a heterogeneous blend of penta- to hepta-acylated species carrying a nonstoichiometric hopanoid unit and possessing very-long-chain fatty acids ranging from 26:0(25-OH) to 32:0(31-OH). The structure of the core oligosaccharide region, fully characterized for the first time here, is revealed to be a nonphosphorylated linear chain with methylated sugar residues, with a heptose residue exclusively present in the outer core region, and with the presence of two singly substituted 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) residues, one of which is located in the outer core region. The lipid A moiety is linked to the core moiety through an uncommon 4-substituted Kdo unit.

  • Di Lorenzo, F.
  • Palmigiano, A.
  • Duda, K. A.
  • Pallach, M.
  • Busset, N.
  • Sturiale, L.
  • Giraud, E.
  • Garozzo, D.
  • Molinaro, A.
  • Silipo, A.

Keywords

  • NMR spectroscopy
  • bradyrhizobium ORS285
  • lipooligosaccharides
  • mass spectrometry
  • symbiosis
Publication details
DOI: 10.1002/open.201700074
Journal: ChemistryOpen
Pages: 541-553 
Number: 4
Work Type: Original
Location: ARCN
Disease Area: General Lung and Other
Partner / Member: FZB
Access-Number: 28794950
See publication on PubMed

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