title: Characterization of the nitrate-nitrite transporter of the major facilitator superfamily (the nrtP gene product) from the cyanobacterium Nostoc punctiforme strain ATCC 29133.
abstract: The products of the NpR1527 and NpR1526 genes of the filamentous, diazotrophic, fresh-water cyanobacterium Nostoc punctiforme strain ATCC 29133 were identified as a nitrate transporter (NRT) and nitrate reductase (NR) respectively, by complementation of nitrate assimilation mutants of the cyanobacterium Synechococcus elongatus strain PCC 7942. While other fresh-water cyanobacteria, including S. elongatus, have an ATP-binding cassette (ABC)-type NRT, the NRT of N. punctiforme belongs to the major facilitator superfamily, being orthologous to the one found in marine cyanobacteria (NrtP). Unlike the ABC-type NRT, which transports both nitrate and nitrite with high affinity, Nostoc NrtP transported nitrate preferentially over nitrite. NrtP was distinct from ABC-type NRT also in its insensitivity to ammonium-promoted regulation at the post-translational level. The nitrate reductase of N. punctiforme was, on the other hand, inhibited upon addition of ammonium to medium, lending ammonium sensitivity to nitrate assimilation.
authors.affiliation: Department of Biological Chemistry, Chubu University, Kasugai, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Aichi
authors.forename: Saori
authors.initials: S
authors.lastname: Yoshihara
authors.forename: Madoka
authors.initials: M
authors.lastname: Yamashita
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Maeda
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagai
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Omata
mesh_terms: D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family / Q000235:genetics; D000091285:Nitrate Transporters; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D046937:Nostoc / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology
chemical_list: D027321:Anion Transport Proteins; D001426:Bacterial Proteins; D000091285:Nitrate Transporters; D009566:Nitrates; D009573:Nitrites; D000644:Quaternary Ammonium Compounds