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Characterization of the membrane‐bound nitrate reductase activity of aerobically grown chlorate‐sensitive mutants of escherichia coli K12
Author(s) -
Giordano Gérard,
Graham Alec,
Boxer David H.,
Haddock Bruce A.,
Azoulay Edgard
Publication year - 1978
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(78)81013-8
Subject(s) - chlorate , escherichia coli , nitrate reductase , chemistry , mutant , biochemistry , nitrate , enzyme , microbiology and biotechnology , biology , inorganic chemistry , organic chemistry , gene
Wild-type strains of Escherichia coli can grow in the presence of chlorate aerobically but under anaerobic conditions growth is inhibited. This observation has been explained on the assumption that under anaerobic conditions, chlorate, an analogue of nitrate, induces nitrate reductase (EC 1.7.99.4) and is converted by the enzyme to the toxic compound chlorite with the result that cell growth ceases: aerobic growth in the presence of chlorate is allowed since under these conditions nitrate reductase activity is repressed [ 11. Recently mutants have been isolated which show a chlorate-sensitive phenotype when grown under aerobic conditions in the presence of a fermentable carbon source [2] and a detailed biochemical characterization of one of these mutants, strain 72, has indicated that the primary genetic lesion occurs in the biosynthetic pathway for ubiquinone8 [3]. In addition, it was noticed that strain 72, when grown aerobically in the presence of nitrate, produced significantly higher activities of reduced benzylviologen-dependent nitrate reductase than an equivalent culture of the parent strain similarly grown, however this activity represented only 2-10% of that found in cultures of either strain 72 or the wild-type grown anaerobically in the presence ofnitrate [2,3]. The nitrate reductase activity found in aerobically-grown strain 72 was destroyed