Pleiotropic role of the Sco1/SenC family copper chaperone in the physiology of Streptomyces.
Bottom Line: The scoC mutant of S. griseus was also defective in the extracellular activity oxidizing N,N'-dimethyl-p-phenylenediamine sulfate.Addition of 10 µM CuSO(4) repressed the activity of the conserved promoter preceding scoA and caused phenylalanine auxotrophy in some Streptomyces spp. probably because of the repression of pheA; pheA encodes prephenate dehydratase, which is located at the 3' terminus of the putative operon structure.Overall, the evidence indicates that Sco is crucial for the utilization of copper under a low-copper condition and for the activation of the multiple Cu(2+) -containing oxidases that play divergent roles in the complex physiology of Streptomyces.
Affiliation: Life Science Research Center, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Japan.Show MeSH
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Mentions: The conserved tandem localization of the sco genes suggested that these coding sequences constitute a polycistron and that their expression is repressed simultaneously by exogenous copper. This raised the possibility that phenylalanine biosynthesis is repressed by copper because pheA is a constituent of the proposed operon structure. Hence, we studied growth on minimal medium, and discovered that exogenous CuSO4 caused phenylalanine auxotrophy in S. coelicolor A3(2) and S. avermitilis; these organisms did not grow on minimal agar media supplied with 10 µM CuSO4 but did grow on media supplemented with phenylalanine (Fig. 8). This is probably due to the dependence of pheA expression on the transcription from the copper‐repressive promoter preceding scoA in these two species. On the other hand, the growth of S. griseus on the medium supplied with CuSO4 indicates that pheA of this organism is transcribed by another promoter. The long intergenic region (285 bp) between scoF and pheA of S. griseus may contain a promoter region. We also assessed the growth of four environmental isolates and found that the two strains exhibited copper‐dependent phenylalanine auxotrophy (Fig. 8).
Affiliation: Life Science Research Center, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Japan.