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Molybdenum-sensitive transcriptional regulation of the chlD locus of Escherichia coli

Journal Article · · J. Bacteriol.; (United States)
OSTI ID:6216788
; ;
The chlD gene in Escherichia coli is required for the incorporation and utilization of molybdenum when the cells are grown with low concentrations of molybdate. The authors constructed chlD-lac operon fusions and measured expressions of the fusion, Mo cofactor, and nitrate reductase activities under a variety of growth conditions. The chlD-lac fusion was highly expressed when cells were grown with less than 10 nm molybdate. Increasing concentrations of molybdate caused loss of activity, with less than 5% of the activity remaining at 500 nM molybdate; when tungstate replaced molybdate, it had an identical affect on chlD expression. Expression of chlD-lac was increased in cells grown with nitrate. Strains with chlD-lac plus an additional mutation in a chl or nar gene were constructed to test whether the regulation of chlD-lac required the concerted action of gene products involved with Mo cofactor or nitrate reductase synthesis. Mutations in narL prevented the increase in activity in response to nitrate; mutations in chlB, narC, or narI resulted in partial constitutive expression of the chlD-lac fusion: the fusion was regulated by molybdate, but it no longer required the presence of nitrate for maximal activity. Mutations in chlA, chlE, or chlG which affect Mo cofactor metabolism, did not affect the expression of chlD-lac.
Research Organization:
Univ. of California, Berkeley
OSTI ID:
6216788
Journal Information:
J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 169:5; ISSN JOBAA
Country of Publication:
United States
Language:
English

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Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
ELEMENTS
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
GENE MUTATIONS
GENE OPERONS
GENE REGULATION
GENE REPRESSORS
GENES
METABOLISM
METALS
MICROORGANISMS
MOLYBDENUM
MUTATIONS
NITRATES
NITROGEN COMPOUNDS
NUCLEOPROTEINS
ORGANIC COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PROTEINS
SENSITIVITY
TOXICITY
TRANSCRIPTION
TRANSITION ELEMENTS