Insights into membrane association of Klebsiella pneumoniae NifL under nitrogen-fixing conditions from mutational analysis.

ABSTRACT: In Klebsiella pneumoniae nitrogen fixation is tightly controlled in response to ammonium and molecular oxygen by the NifL/NifA regulatory system. Under repressing conditions, NifL inhibits the nif-specific transcriptional activator NifA by direct protein-protein interaction, whereas under anaerobic and nitrogen-limited conditions sequestration of reduced NifL to the cytoplasmic membrane impairs inhibition of cytoplasmic NifA by NifL. We report here on a genetic screen to identify amino acids of NifL essential for sequestration to the cytoplasmic membrane under nitrogen-fixing conditions. Overall, 11,500 mutated nifL genes of three independently generated pools were screened for those conferring a Nif(-) phenotype. Based on the respective amino acid changes of nonfunctional derivatives obta

SUBMITTER: Milenkov M 

PROVIDER: S-EPMC3021237 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature