In Azotobacter vinelandii, the E1 subunit of the pyruvate dehydrogenase complex binds fpr promoter region DNA and ferredoxin I

AUTOR(ES)

Regnström, Karin

FONTE

The National Academy of Sciences

RESUMO

In Azotobacter vinelandii, deletion of the fdxA gene that encodes a well characterized seven-iron ferredoxin (FdI) is known to lead to overexpression of the FdI redox partner, NADPH:ferredoxin reductase (FPR). Previous studies have established that this is an oxidative stress response in which the fpr gene is transcriptionally activated to the same extent in response to either addition of the superoxide propagator paraquat to the cells or to fdxA deletion. In both cases, the activation occurs through a specific DNA sequence located upstream of the fpr gene. Here, we report the identification of the A. vinelandii protein that binds specifically to the paraquat activatable fpr promoter region as the E1 subunit of the pyruvate dehydrogenase complex (PDHE1), a central enzyme in aerobic respiration. Sequence analysis shows that PDHE1, which was not previously suspected to be a DNA-binding protein, has a helix–turn–helix motif. The data presented here further show that FdI binds specifically to the DNA-bound PDHE1.

Documentos Relacionados

• RIBONUCLEIC ACID POLYMERASE OF AZOTOBACTER VINELANDII, I. PRIMING BY POLYRIBONUCLEOTIDES*
• Structure of ferredoxin I from Azotobacter vinelandii.
• Mitochondrial pyruvate dehydrogenase. Molecular cloning of the E1 alpha subunit and expression analysis.
• Spectroscopic studies of ferricyanide oxidation of Azotobacter vinelandii ferredoxin I.
• Construction and characterization of an Azotobacter vinelandii strain with mutations in the genes encoding flavodoxin and ferredoxin I.