title: Unusual outer membrane lipid composition of the gram-negative, lipopolysaccharide-lacking myxobacterium Sorangium cellulosum So ce56.
abstract: The gram-negative myxobacterium Sorangium cellulosum So ce56 bears the largest bacterial genome published so far, coding for nearly 10,000 genes. Careful analysis of this genome data revealed that part of the genes coding for the very well conserved biosynthesis of lipopolysaccharides (LPS) are missing in this microbe. Biochemical analysis gave no evidence for the presence of LPS in the membranes of So ce56. By analyzing the lipid composition of its outer membrane sphingolipids were identified as the major lipid class, together with ornithine-containing lipids (OL) and ether lipids. A detailed analysis of these lipids resulted in the identification of more than 50 structural variants within these three classes, which possessed several interesting properties regarding to LPS replacement, mediators in myxobacterial differentiation, as well as potential bioactive properties. The sphingolipids with the basic structure C9-methyl-C(20)-sphingosine possessed as an unusual trait C9-methylation, which is common to fungi but highly uncommon to bacteria. Such sphingolipids have not been found in bacteria before, and they may have a function in myxobacterial development. The OL, also identified in myxobacteria for the first time, contained acyloxyacyl groups, which are also characteristic for LPS and might replace those in certain functions. Finally, the ether lipids may serve as biomarkers in myxobacterial development.
authors.affiliation: Department of Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Keck
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gisch
authors.forename: Hermann
authors.initials: H
authors.lastname: Moll
authors.forename: Frank-Jörg
authors.initials: FJ
authors.lastname: Vorhölter
authors.forename: Klaus
authors.initials: K
authors.lastname: Gerth
authors.forename: Uwe
authors.initials: U
authors.lastname: Kahmann
authors.forename: Manfred
authors.initials: M
authors.lastname: Lissel
authors.forename: Buko
authors.initials: B
authors.lastname: Lindner
authors.forename: Karsten
authors.initials: K
authors.lastname: Niehaus
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
mesh_terms: D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial / Q000502:physiology; D008070:Lipopolysaccharides; D008563:Membrane Lipids / Q000235:genetics / Q000378:metabolism*; D009231:Myxococcales / Q000235:genetics / Q000378:metabolism*
chemical_list: D008070:Lipopolysaccharides; D008563:Membrane Lipids