title: MprF-mediated biosynthesis of lysylphosphatidylglycerol, an important determinant in staphylococcal defensin resistance.
abstract: Frequently bacteria are exposed to membrane-damaging cationic antimicrobial molecules (CAMs) produced by the host's immune system (defensins, cathelicidins) or by competing microorganisms (bacteriocins). Staphylococcus aureus achieves CAM resistance by modifying anionic phosphatidylglycerol with positively charged L-lysine, resulting in repulsion of the peptides. Inactivation of the novel S. aureus gene, mprF, which is found in many bacterial pathogens, has resulted in the loss of lysylphosphatidylglycerol (L-PG), increased inactivation by CAM-containing neutrophils, and attenuated virulence. We demonstrate here that expression of mprF is sufficient to confer L-PG production in Escherichia coli, which indicates that MprF represents the L-PG synthase. L-PG biosynthesis was studied in vitro and found to be dependent on phosphatidylglycerol and lysyl-tRNA, two putative substrate molecules. Further addition of cadaverin, a competitive inhibitor of the lysyl-tRNA synthetases, or of RNase A abolished L-PG biosynthesis, thereby confirming the involvement of lysyl-tRNA. This study forms the basis for further detailed analyses of L-PG biosynthesis and its role in bacterial infections.
authors.affiliation: Cellular and Molecular Microbiology, Medical Microbiology Department, University of Tübingen, Elfriede-Aulhorn-Str. 6, D-72076 Tübingen, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Staubitz
authors.forename: Heinz
authors.initials: H
authors.lastname: Neumann
authors.forename: Tanja
authors.initials: T
authors.lastname: Schneider
authors.forename: Imke
authors.initials: I
authors.lastname: Wiedemann
authors.forename: Andreas
authors.initials: A
authors.lastname: Peschel
mesh_terms: D019881:Aminoacyltransferases; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D023082:Defensins / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D008239:Lysine; D008246:Lysophospholipids / Q000096:biosynthesis* / Q000494:pharmacology; D010715:Phosphatidylglycerols; D013211:Staphylococcus aureus / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D023082:Defensins; D008246:Lysophospholipids; D010715:Phosphatidylglycerols; C002285:lysylphosphatidylglycerol; D019881:Aminoacyltransferases; C429146:mprF protein, Staphylococcus aureus; D008239:Lysine