title: Physicochemical characterization and biological activity of a glycoglycerolipid from Mycoplasma fermentans.
abstract: We report a comprehensive physicochemical characterization of a glycoglycerolipid from Mycoplasma fermentans, MfGl-II, in relation to its bioactivity and compared this with the respective behaviors of phosphatidylcholine (PC) and a bacterial glycolipid, lipopolysaccharide (LPS) from deep rough mutant Salmonella minnesota strain R595. The beta left arrow over right arrow alpha gel-to-liquid crystalline phase transition behavior of the hydrocarbon chains with Tc = 30 degrees C for MfGl-II as well as for LPS exhibits high similarity between the two glycolipids. A lipopolysaccharide-binding protein (LBP)-mediated incorporation into negatively charged liposomes is observed for both glycolipids. The determination of the supramolecular aggregate structure confirms the existence of a mixed unilamellar/cubic structure for MfGl-II, similar to that observed for the lipid A moiety of LPS. The biological data clearly show that MfGl-II is able to induce cytokines such as tumor necrosis factor-alpha (TNF-alpha) in human mononuclear cells, although to a significantly lower degree than LPS. In contrast, in the Limulus amebocyte lysate test, MfGl-II is completely inactive, and in the CHO reporter cell line it does not indicate any reactivity with the Toll-like receptors TLR-2 and -4, in contrast to control lipopeptides and LPS. These data confirm the applicability of our conformational concept of endotoxicity to nonlipid A structures: an amphiphilic molecule with a nonlamellar cubic aggregate structure corresponding to a conical conformation of the single molecules and a sufficiently high negative charge density in the backbone.
authors.affiliation: Forschungszentrum Borstel, Center for Medicine and Biosciences, Borstel, Germany. kbranden@fz-borstel.de
authors.forename: Klaus
authors.initials: K
authors.lastname: Brandenburg
authors.forename: Frauke
authors.initials: F
authors.lastname: Wagner
authors.forename: Mareike
authors.initials: M
authors.lastname: Müller
authors.forename: Holger
authors.initials: H
authors.lastname: Heine
authors.forename: Jörg
authors.initials: J
authors.lastname: Andrä
authors.forename: Michel H J
authors.initials: MH
authors.lastname: Koch
authors.forename: Ulrich
authors.initials: U
authors.lastname: Zähringer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Seydel
mesh_terms: D000209:Acute-Phase Proteins; D000818:Animals; D016466:CHO Cells; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D017930:Genes, Reporter; D006017:Glycolipids / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D008033:Limulus Test; D008070:Lipopolysaccharides / Q000737:chemistry / Q000494:pharmacology; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D008968:Molecular Conformation; D016858:Mycoplasma fermentans / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D006017:Glycolipids; D008070:Lipopolysaccharides; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D010713:Phosphatidylcholines; D014409:Tumor Necrosis Factor-alpha; D000099231:Lipopolysaccharide-Binding Protein; C433512:6'-O-(3''-phosphocholine-2''-aminio-1'-phospho-1'',3''-propanediol)-glucopyranosyl-(1'-3')-1,2-diacylglycerol