title: PnuC and the utilization of the nicotinamide riboside analog 3-aminopyridine in Haemophilus influenzae.
abstract: The utilization pathway for the uptake of NAD and nicotinamide riboside was previously characterized for Haemophilus influenzae. We now report on the cellular location, topology, and substrate specificity of PnuC. pnuC of H. influenzae is only distantly related to pnuC of Escherichia coli and Salmonella enterica serovar Typhimurium. When E. coli PnuC was expressed in an H. influenzae pnuC mutant, it was able to take up only nicotinamide riboside and not nicotinamide mononucleotide. Therefore, we postulated that PnuC transporters in general possess specificity for nicotinamide riboside. Earlier studies showed that 3-aminopyridine derivatives (e.g., 3-aminopyridine adenine dinucleotide) are inhibitory for H. influenzae growth. By testing characterized strains with mutations in the NAD utilization pathway, we show that 3-aminopyridine riboside is inhibitory to H. influenzae and is taken up by the NAD-processing and nicotinamide riboside route. 3-Aminopyridine riboside is utilized effectively in a pnuC+ background. In addition, we demonstrate that 3-aminopyridine adenine dinucleotide resynthesis is produced by NadR. 3-Aminopyridine riboside-resistant H. influenzae isolates were characterized, and mutations in nadR could be detected. We also tested other species of the family Pasteurellaceae, Pasteurella multocida and Actinobacillus actinomycetemcomitans, and found that 3-aminopyridine riboside does not act as a growth inhibitor; hence, 3-aminopyridine riboside represents an anti-infective agent with a very narrow host range.
authors.affiliation: Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany.
authors.forename: Elizabeta
authors.initials: E
authors.lastname: Sauer
authors.forename: Melisa
authors.initials: M
authors.lastname: Merdanovic
authors.forename: Anne Price
authors.initials: AP
authors.lastname: Mortimer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Bringmann
authors.forename: Joachim
authors.initials: J
authors.lastname: Reidl
mesh_terms: D000469:Alkaline Phosphatase; D000595:Amino Acid Sequence; D000631:Aminopyridines / Q000378:metabolism / Q000494:pharmacology*; D015153:Blotting, Western; D002855:Chromatography, Thin Layer; D003001:Cloning, Molecular; D003470:Culture Media; D018844:Cyclin-Dependent Kinases / Q000235:genetics; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D007763:Lac Operon / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000631:Aminopyridines; D003470:Culture Media; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D009243:NAD; C031283:3-aminopyridine; D018844:Cyclin-Dependent Kinases; D000469:Alkaline Phosphatase; C114089:phoA protein, E coli