Chemical structure of the somatic antigen isolated from Salmonella Abortusequi (O4)

Bacterial Lipopolysaccharides: An Overview of Their Structure, Biosynthesis and Immunological Activity

“…Despite their general architecture, lipid A moieties also present a sort of microheterogeneity due to the presence of subtle chemical differences depending on a wide number of factors including bacterial adaptation, incomplete biosynthesis, changing of environment, presence of external stimuli and chemical modifications resulting from the procedures used for lipid A extraction from bacterial cells. Microheterogeneity has been observed in the acylation (number, type and distribution of acyl chains) and phosphorylation patterns, and less commonly, also in the disaccharide backbone, as in the case of a number of bacterial species, such as Aquifex pyrophilus [19], Brucella abortus [20], Bacteriovorax stolpii [21], Caulobacter crescentus [22], Mesorhizobium huakuii [23], Bradyrhizobium elkanii [24], Bartonella henselae [25], Legionella pneumophila [26], whose glucosamine (GlcN) residues may be replaced with 2,3-diamino-2,3-dideoxy-D-glucopyranose (GlcpN3N) residues. Moreover, phosphate groups can be substituted by further phosphate groups, producing a pyrophosphate, but also by other polar substituents, such as 4-amino-4-deoxy-L-arabinopyranose (arabinosamine, Arap4N) and 2-amino-ethanol groups (EtN), or by acid residues, such as galacturonic acid (GalpA).…”