Heterologous NNR-mediated nitric oxide signaling in Escherichia coli.

ABSTRACT: The transcription factor NNR from Paracoccus denitrificans was expressed in a strain of Escherichia coli carrying a plasmid-borne fusion of the melR promoter to lacZ, with a consensus FNR-binding site 41.5 bp upstream of the transcription start site. This promoter was activated by NNR under anaerobic growth conditions in media containing nitrate, nitrite, or the NO(+) donor sodium nitroprusside. Activation by nitrate was abolished by a mutation in the molybdenum cofactor biosynthesis pathway, indicating a requirement for nitrate reductase activity. Activation by nitrate was modulated by the inclusion of reduced hemoglobin in culture media, because of the ability of hemoglobin to sequester nitric oxide and nitrite. The ability of nitrate and nitrite to activate NNR is likely due to the form

SUBMITTER: Hutchings MI 

PROVIDER: S-EPMC94790 | biostudies-literature | 2000 Nov

REPOSITORIES: biostudies-literature