Effects of Perturbations of the Nitrogenase Electron Transfer Chain on Reversible ADP-Ribosylation of Nitrogenase Fe Protein in Klebsiella pneumoniae Strains Bearing the Rhodospirillum rubrum dra Operon
AUTOR(ES)
Halbleib, Cale M.
FONTE
American Society for Microbiology
RESUMO
The redox state of nitrogenase Fe protein is shown to affect regulation of ADP-ribosylation in Klebsiella pneumoniae strains transformed by plasmids carrying dra genes from Rhodospirillum rubrum. The dra operon encodes dinitrogenase reductase ADP-ribosyltransferase and dinitrogenase reductase-activating glycohydrolase, enzymes responsible for the reversible inactivation, via ADP-ribosylation, of nitrogenase Fe protein in R. rubrum. In bacteria containing the dra operon in their chromosomes, inactivation occurs in response to energy limitation or nitrogen sufficiency. The dra gene products, expressed at a low level in K. pneumoniae, enable transformants to reversibly ADP-ribosylate nitrogenase Fe protein in response to the presence of fixed nitrogen. The activities of both regulatory enzymes are regulated in vivo as described in R. rubrum. Genetic perturbations of the nitrogenase electron transport chain were found to affect the rate of inactivation of Fe protein. Strains lacking the electron donors to Fe protein (NifF or NifJ) were found to inactivate Fe protein more quickly than a strain with wild-type background. Deletion of nifD, which encodes a subunit of nitrogenase MoFe protein, was found to result in a slower inactivation response. No variation was found in the reactivation responses of these strains. It is concluded that the redox state of the Fe protein contributes to the regulation of the ADP-ribosylation of Fe protein.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=94538Documentos Relacionados
- Reversible regulation of the nitrogenase iron protein from Rhodospirillum rubrum by ADP-ribosylation in vitro.
- Mutations in the draT and draG genes of Rhodospirillum rubrum result in loss of regulation of nitrogenase by reversible ADP-ribosylation.
- Reversible ADP-ribosylation of dinitrogenase reductase in a nifD- mutant of Rhodospirillum rubrum.
- ADP-ribosylation of an approximately 70-kilodalton protein of Klebsiella pneumoniae.
- ADP-Ribosylation of Variants of Azotobacter vinelandii Dinitrogenase Reductase by Rhodospirillum rubrum Dinitrogenase Reductase ADP-Ribosyltransferase