Proteomic Approach to Reveal the Regulatory Function of Aconitase AcnA in Oxidative Stress Response in the Antibiotic Producer <i>Streptomyces viridochromogenes</i> Tü494

<div><p>The aconitase AcnA from the phosphinothricin tripeptide producing strain <i>Streptomyces viridochromogenes</i> Tü494 is a bifunctional protein: under iron-sufficiency conditions AcnA functions as an enzyme of the tricarboxylic acid cycle, whereas under iron depletion it is a regulator of iron metabolism and oxidative stress response. As a member of the family of iron regulatory proteins (IRP), AcnA binds to characteristic iron responsive element (IRE) binding motifs and post-transcriptionally controls the expression of respective target genes. A <i>S. viridochromogenes</i> aconitase mutant (MacnA) has previously been shown to be highly sensitive to oxidative stress. In the present paper, we performed a comparative proteomic approach with the <i>S. viridochromogenes</i> wild-type and the MacnA mutant strain under oxidative stress conditions to identify proteins that are under control of the AcnA-mediated regulation. We identified up to 90 differentially expressed proteins in both strains. <i>In silico</i> analysis of the corresponding gene sequences revealed the presence of IRE motifs on some of the respective target mRNAs. From this proteome study we have <i>in vivo</i> evidences for a direct AcnA-mediated regulation upon oxidative stress.</p></div

Proteins directly regulated by AcnA.

*<p>Distance of the IRE-like motifs in base pairs from start or stop codon.</p