title: NAD biosynthesis: identification of the tryptophan to quinolinate pathway in bacteria.
abstract: Previous studies have demonstrated two different biosynthetic pathways to quinolinate, the universal de novo precursor to the pyridine ring of NAD. In prokaryotes, quinolinate is formed from aspartate and dihydroxyacetone phosphate; in eukaryotes, it is formed from tryptophan. It has been generally believed that the tryptophan to quinolinic acid biosynthetic pathway is unique to eukaryotes; however, this paper describes the use of comparative genome analysis to identify likely candidates for all five genes involved in the tryptophan to quinolinic acid pathway in several bacteria. Representative examples of each of these genes were overexpressed, and the predicted functions are confirmed in each case using unambiguous biochemical assays.
authors.affiliation: Integrated Genomics, 2201 West Campbell Park Drive, Chicago, IL 60612, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Kurnasov
authors.forename: Vasiliy
authors.initials: V
authors.lastname: Goral
authors.forename: Keri
authors.initials: K
authors.lastname: Colabroy
authors.forename: Svetlana
authors.initials: S
authors.lastname: Gerdes
authors.forename: Shubha
authors.initials: S
authors.lastname: Anantha
authors.forename: Andrei
authors.initials: A
authors.lastname: Osterman
authors.forename: Tadhg P
authors.initials: TP
authors.lastname: Begley
mesh_terms: D005558:Arylformamidase / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D005816:Genetic Complementation Test; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009243:NAD / Q000096:biosynthesis* / Q000737:chemistry; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D017378:Quinolinic Acid / Q000737:chemistry / Q000378:metabolism*; D014364:Tryptophan / Q000737:chemistry / Q000378:metabolism*
chemical_list: D009243:NAD; D014364:Tryptophan; D010088:Oxidoreductases; D006867:Hydrolases; D005558:Arylformamidase; C021480:kynureninase; D017378:Quinolinic Acid