title: Isotopologue profiling of the listerial N-metabolism.
abstract: The nitrogen (N-) sources and the relative contribution of a nitrogenous nutrient to the N-pool of the gram-positive pathogen Listeria monocytogenes are largely unknown. Therefore, (15) N-isotopologue profiling was established to study the N-metabolism of L. monocytogenes. The pathogen was grown in a defined minimal medium supplemented with potential (15) N-labeled nutrients. The bacteria were harvested and hydrolysed under acidic conditions, and the resulting amino acids were analysed by GC-MS, revealing (15) N-enrichments and isotopomeric compositions of amino acids. The differential (15) N-profiles showed the substantial and simultaneous usage of ammonium, glutamine, methionine, and, to a lower extent, the branched-chain amino acids valine, leucine, and isoleucine for anabolic purposes, with a significant preference for ammonium. In contrast, arginine, histidine and cysteine were directly incorporated into proteins. L. monocytogenes is able to replace glutamine with ethanolamine or glucosamine as amino donors for feeding the core N-metabolism. Perturbations of N-fluxes caused by gene deletions demonstrate the involvement of ethanolamine ammonia lyase, and suggest a role of the regulator GlnK of L. monocytogenes distinct from that of Escherichia coli. The metabolism of nitrogenous nutrients reflects the high flexibility of this pathogenic bacterium in exploiting N-sources that could also be relevant for its proliferation during infection.
authors.affiliation: Lehrstuhl für Biochemie, Technische Universität München, D-85747, Garching, Germany.
authors.forename: Erika
authors.initials: E
authors.lastname: Kutzner
authors.affiliation: Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Kern
authors.affiliation: Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Felsl
authors.affiliation: Lehrstuhl für Biochemie, Technische Universität München, D-85747, Garching, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.affiliation: Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
authors.forename: Thilo M
authors.initials: TM
authors.lastname: Fuchs
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D007532:Isoleucine / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008087:Listeria / Q000378:metabolism; D008089:Listeria monocytogenes / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000032:analysis; D011506:Proteins / Q000378:metabolism
chemical_list: D000596:Amino Acids; D009587:Nitrogen Isotopes; D011506:Proteins; D007532:Isoleucine; D007930:Leucine; D009584:Nitrogen