Enterobacterial lipid

Single crystals of free lipid A or LPS are as yet not available. Therefore, the most promising approach to obtain molecular models is to perform theoretical calculations. After the chemical structures of enterobacterial lipid A had been elucidated, this methodology was successfully applied with heptaacyl S. minnesota lipid A (220) and hexaacyl E. coli Re LPS (221). As an example, Fig. 13 shows the atomic model of the E. coli lipid A molecule, as calculated by Kastowsky et al. (221) using energy-minimization techniques. 

A very similar or identical backbone has later been identified in a number of other enterobacterial lipid A s including that of Escherichia coli, Proteus mirabilis, Shigella sonnei, Shigella flexneri, Yersinia enterocolitica and Serratia marces-... 

Jurgens G, Muller M, Koch MH, et al. Interaction of hemoglobin with enterobacterial lipopolysaccharide and lipid A. Physicochemical characterization and biological activity. Eur J Biochem 2001 268 4233. 

The endotoxlc activity associated with Gram-negative bacterial infections resides in the lipophilic lipid A part of the LPS molecule (1). This toxic activity manifests itself in a number of ways, e.g., pyrogenicity, transient leucopenla followed by leucocytosis, hypotension, bone marrow necrosis, abortion, the Shwartzman reaction, etc. As a consequence the commonly used killed whole cell enterobacterial vaccines have to be given in... 

With respect to polysaccharides, N-acetylneuraminic acid and KDO are unusual components. Rather, N-acetylneuraminic acid is a constituent of glycoproteins and certain glycolipids - and KDO is characteristically found in enterobacterial lipopolysaccharides, where it forms the linkage region between the lipid and carbohydrate moieties. 

Like Escherichia coli, clinical isolates of H. pylori produce high-molecular-mass (smooth-form) lipopolysaccharide (LPS) composed of an outermost saccharide moiety, divided into the O-polysaccharide or O-specific chain (O-antigen) and core oligosaccharide (OS) regions, covalently linked to lipid A (Fig. 10.1). H. pylori smooth-form LPS possesses O-polysaccharide chains of relatively constant chain length compared with those of enterobacterial LPS (Moran et al., 1992a Moran, 1999). Their length is determined by an enzymatic molecular ruler mechanism... 

Lipopolysaccharides.— Recent reviews have dealt with the compositions and the structures of bacterial lipopolysaccharides/ the serological properties, chemistry, and genetics of the O antigens from E. coli, the enterobacterial common antigen, the involvement of lipids in the biosynthesis of lipopolysaccharides, and the binding of bacteriophages to O antigens. ... 

Seydel, U. Lindner, B. Wollenweber, H.-W. Rietschel, E. T. Structural studies on the lipid component of enterobacterial lipopolysaccharides by laser desorption mass spectrometry. Location of acyl groups on the lipid A backbone. Eur. J. Biochem. 1984, 145, 505-509. 

Westphal, O., Gmeiner, J., LtJDERiTz, O., Tanaka, A., Eichenberger, E. Chemistry and biology of the lipid A component of enterobacterial lipopolysaccharides. In Chedid (9). 

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