Open AccessThe Assimilatory and Dissimilatory Nitrate Reductases of Pseudomonas aeruginosa are Encoded by Different Genes
Author(s) -
Stacey R. Sias,
A. H. Stouthamer,
John L. Ingraham
Publication year - 1980
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-118-1-229
Subject(s) - nitrate reductase , nitrate , pseudomonas aeruginosa , mutant , gene , biochemistry , biology , enzyme , reductase , microbiology and biotechnology , chemistry , phenotype , bacteria , genetics , ecology
The phenotypes of certain mutant strains of Pseudomonas aeruginosa were reported to be pleiotropic for nitrate reduction; these strains were selected for their inability to dissimilate nitrate and were found also to have lost the ability to assimilate nitrate. We now report that the isolation procedure selected two mutations, one in genes encoding the synthesis of dissimilatory nitrate reductase (narA, narB or narE) and another in one of the genes (nas) encoding the synthesis of assimilatory nitrate reductase. Thus in P. aeruginosa dissimilatory and assimilatory nitrate reductases are genetically distinct. However, a loss of both enzymes is necessary to prevent slow dissimilatory growth on nitrate. Assimilatory nitrate reductase requires molybdenum to function, as does dissimilatory nitrate reductase. Lesions in narD affect incorporation of molybdenum into both enzymes, and hence exert a pleiotropic effect.