Cloning and analysis of the tomato nitrate reductase-encoding gene: protein domain structure and amino acid homologies in higher plants.
We have cloned and sequenced the nitrate reductase (NR)-encoding gene (nia) from tomato. When compared to the two Nicotiana tabacum nia structural genes, this 5-kb tomato gene shows a highly conserved structure, the coding sequence being interspersed with three introns at the same positions. Nucleotide sequences of the 5' promoter regions are not homologous, except for a 250-bp fragment. This small region might be involved in the similar regulation of the nia expression in tomato and tobacco plant species. The tomato gene codes for a 911 amino acid (aa) polypeptide chain. This sequence was aligned with and compared to other higher plant NR sequences. This alignment clearly identifies the three catalytic domains of NR, namely, a molybdopterin cofactor-binding domain, a heme domain and a FAD/NADH domain. On the other hand, it suggests that the less conserved 80-aa N-terminal region, containing a striking acidic aa cluster, is an additional domain bearing regulatory or structural function.
Daniel-Vedele
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F
Laboratoire de Biologie Cellulaire, INRA, Versailles, France.
Dorbe
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MF
Caboche
M
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Rouzé
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P
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009565:Nitrate Reductases / Q000235:genetics*; D010944:Plants / Q000201:enzymology / Q000235:genetics*; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid
D004247:DNA; D009565:Nitrate Reductases