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Isolation and structural analysis of two lipid A precursors from a KDO deficient mutant of Salmonella typhimurium differing in their hexadecanoic acid content (1985)

Hansen-Hagge, Thomas ; Lehmann, Volker ; Seydel, Ulrich ; [et al.]

Springer

Archives of microbiology 141 (1985), S. 353-358

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ISSN: 1432-072X

Keywords: KDO mutant ; Lipid A intermediates ; Hexadecanoic acid substitution ; Biosynthesis of lipid A

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The extraction, purification and structural characterization of two lipid A precursors (Ia and Ib) differing only in one hexadecanoic acid are described. Both precursors were synthesized at elevated temperatures by a new mutant of Salmonella typhimurium (mutant Ts5) which is conditionally defective in synthesis of the 3-deoxy-d-manno-octulosonic acid region of lipopolysaccharides. Both precursors were purified by repeated phenol/chloroform/petroleum ether (PCP) extractions followed by thin layer chromatography. Teh precursor preparation was free of lipopolysaccharides and phospholipids and contained less than 0.1% protein. Structural analysis which included chemical degradation procedures as well as positive ion laser desorption (LDMS) mass spectroscopy of dephosphorylated lipid A precursors showed together that precursor Ia represents a diphosphorylated glucosamine disaccharide containing two ester, two amide-linked residues of 3-hydroxytetradecanoic acid and lacks the ester-linked dodecanoic, tetradecanoic and hexadecanoic acid as well as 3-deoxy-d-manno-octulosonic acid. Precursor Ib has the same basic structure as precursor Ia, but contains in addition one mol of hexadecanoic acid per mol disaccharide which is linked to the 3-hydroxy group of the amide-bound 3-hydroxy-tetradecanoic acid of the reducing, terminal glucosamine residue. The structure of precursor Ib supports the conclusion that hexadecanoic acid incorporation occurs at an early stage in lipid A biosynthesis prior to the attachment of 3-deoxy-d-manno-octulosonic acid and/or other polar substituents.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00428849

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Laser desorption mass spectrometry of synthetic lipid a-like compounds (1984)

Seydel, Ulrich ; Lindner, Buko ; Zähringer, Ulrich ; [et al.]

Chichester : Wiley-Blackwell

Biological Mass Spectrometry 11 (1984), S. 132-141

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ISSN: 0306-042X

Keywords: Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The applicability and the present limitations of the laser microprobe mass analyser LAMMA®-500 as an instrument for the structural analysis of higher molecular weight, non-volatile, bio-organic compounds (≤2000 u) were investigated. For this purpose mass spectra of various synthetic and natural compounds representing cell wall components of Gram-negative bacteria, e.g. phospholipids and lipid A-like molecules were studied. In several cases these spectra exhibited relatively simple and interpretable patterns with a prominent quasi-molecular ion originating from alkali attachment. For one group of the compounds studied - synthetic lipid A-like molecules containing a phosphate moiety - the spectra were rather complicated and lacked pronounced quasi-molecular peaks. Possible reasons for this observation are discussed.

Additional Material: 12 Ill.