Characterization of the nitrate-nitrite transporter of the major facilitator superfamily (the nrtP gene product) from the cyanobacterium Nostoc punctiforme strain ATCC 29133.
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.
Aichi
Makiko
M
Department of Biological Chemistry, Chubu University, Kasugai, Japan.
Yoshihara
Saori
S
Yamashita
Madoka
M
Maeda
Shin-ichi
S
Nagai
Kazuo
K
Omata
Tatsuo
T
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
D027321:Anion Transport Proteins; D001426:Bacterial Proteins; D000091285:Nitrate Transporters; D009566:Nitrates; D009573:Nitrites; D000644:Quaternary Ammonium Compounds