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  • The EMBO Journal (2001) 20, 6937 - 6945
  • doi:10.1093/emboj/20.24.6937

Outer membrane composition of a lipopolysaccharide-deficient Neisseria meningitidis mutant

Liana Steeghs1,2,3, Hans de Cock2, Evert Evers4, Bert Zomer4, Jan Tommassen2 and Peter van der Ley1

  1. Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands
  2. Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
  3. Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands
  4. Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands

Correspondence to:

Liana Steeghs, E-mail: liana.steeghs@rivm.nl

Received 19 February 2001; Accepted 1 November 2001; Revised 22 October 2001

In the pathogen Neisseria meningitidis, a completely lipopolysaccharide (LPS)-deficient but viable mutant can be obtained by insertional inactivation of the lpxA gene, encoding UDP-GlcNAc acyltransferase required for the first step of lipid A biosynthesis. To study how outer membrane structure and biogenesis are affected by the absence of this normally major component, inner and outer membranes were separated and their composition analysed. The expression and assembly of integral outer membrane proteins appeared largely unaffected. However, the expression of iron limitation-inducible, cell surface-exposed lipoproteins was greatly reduced. Major changes were seen in the phospholipid composition, with a shift towards phosphatidylethanolamine and phosphatidylglycerol species containing mostly shorter chain, saturated fatty acids, one of which was unique to the LPS-deficient outer membrane. The presence of the capsular polysaccharide turned out to be essential for viability without LPS, as demonstrated by using a strain in which LPS biosynthesis could be switched on or off through a tac promoter-controlled lpxA gene. Taken together, these results can help to explain why meningococci have the unique ability to survive without LPS.

  • Keywords:

    • capsular polysaccharide,
    • lipopolysaccharide,
    • Neisseria meningitidis,
    • outer membrane proteins,
    • phospholipids