Cloning and Characterization of the nrtA Gene That Encodes a 45-kDa Protein Involved in Nitrate Transport in the Cyanobacterium Synechococcus PCC 7942

A 45-kDa protein in the cytoplasmic membrane of the cyanobacteriumSynechococcus PCC 7942 is involved in the active transport ofnitrate Omata et al. (1989) Proc. Natl. Acad. Sci. USA 86:6612]. The gene coding for this protein (designated herein asnrtA) has been cloned and sequenced. The nrtA gene encodes aprotein of 443 amino acids with a calculated molecular weightof 48424. The deduced amino acid sequence of the protein is46.5% homologous to that of a 42-kDa cytoplasmic membrane proteinthat is synthesized under carbon-limited conditions in SynechococcusPCC 7942. (Received July 16, 1990; Accepted December 5, 1990)