title: Multiple targets of nitric oxide in the tricarboxylic acid cycle of Salmonella enterica serovar typhimurium.
abstract: Host nitric oxide (NO⋅) production is important for controlling intracellular bacterial pathogens, including Salmonella enterica serovar Typhimurium, but the underlying mechanisms are incompletely understood. S. Typhmurium 14028s is prototrophic for all amino acids but cannot synthesize methionine (M) or lysine (K) during nitrosative stress. Here, we show that NO⋅-induced MK auxotrophy results from reduced succinyl-CoA availability as a consequence of NO⋅ targeting of lipoamide-dependent lipoamide dehydrogenase (LpdA) activity. LpdA is an essential component of the pyruvate and α-ketoglutarate dehydrogenase complexes. Additional effects of NO⋅ on gene regulation prevent compensatory pathways of succinyl-CoA production. Microarray analysis indicates that over 50% of the transcriptional response of S. Typhimurium to nitrosative stress is attributable to LpdA inhibition. Bacterial methionine transport is essential for virulence in NO⋅-producing mice, demonstrating that NO⋅-induced MK auxotrophy occurs in vivo. These observations underscore the importance of metabolic targets for antimicrobial actions of NO⋅.
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA.
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Richardson
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Payne
authors.forename: Noah
authors.initials: N
authors.lastname: Younger
authors.forename: Joyce E
authors.initials: JE
authors.lastname: Karlinsey
authors.forename: Vinai C
authors.initials: VC
authors.lastname: Thomas
authors.forename: Lynne A
authors.initials: LA
authors.lastname: Becker
authors.forename: William W
authors.initials: WW
authors.lastname: Navarre
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Castor
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Libby
authors.forename: Ferric C
authors.initials: FC
authors.lastname: Fang
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002952:Citric Acid Cycle; D003470:Culture Media; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D054884:Host-Pathogen Interactions; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D008239:Lysine / Q000378:metabolism / Q000494:pharmacology; D008715:Methionine / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D012480:Salmonella Infections / Q000378:metabolism; D012486:Salmonella typhimurium / Q000187:drug effects / Q000378:metabolism* / Q000472:pathogenicity*; D013312:Stress, Physiological; D013385:Succinate Dehydrogenase / Q000235:genetics / Q000378:metabolism
chemical_list: D000214:Acyl Coenzyme A; D003470:Culture Media; D009569:Nitric Oxide; D008715:Methionine; C012046:succinyl-coenzyme A; D007655:Ketoglutarate Dehydrogenase Complex; D013385:Succinate Dehydrogenase; D008058:Dihydrolipoamide Dehydrogenase; D008239:Lysine