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Identification by mutational analysis of four critical residues in the molybdenum cofactor domain of eukaryotic nitrate reductase
Author(s) -
Meyer Christian,
Gonneau Martine,
Caboche Michel,
Rouzé Pierre
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00827-v
Subject(s) - molybdenum cofactor , sulfite oxidase , nitrate reductase , biochemistry , cofactor , mutant , cyclic nucleotide binding domain , reductase , biology , chemistry , enzyme , peptide sequence , gene
The nucleotide sequence of the nitrate reductase (NR) molybdenum cofactor (MoCo) domain was determined in four Nicotiana plumbaginifolia mutants affected in the NR apoenzyme gene. In each case, missense mutations were found in the MoCo domain which affected amino acids that were conserved not only among eukaryotic NRs but also in animal sulfite oxidase sequences. Moreover an abnormal NR molecular mass was observed in three mutants, suggesting that the integrity of the MoCo domain is essential for a proper assembly of holo‐NR. These data allowed to pinpoint critical residues in the NR MoCo domain necessary for the enzyme activity but also important for its quaternary structure.