A DasA family sugar binding protein Ste2 links nutrient and oxidative stress to exopolysaccharides production in Streptomyces sp. 139.

Background: Ebosin is an exopolysaccharide produced by Streptomyces sp. 139, and its biosynthetic gene cluster (ste) has been previously described. Ste234 has high homology to the well-known ATP-binding cassette transport system DasABC, which has been linked to the regulation of morphological differentiation, antibiotics biosynthesis and aminosugars utilization in Streptomycetes. This study was conducted to evaluate the effect of the DasA family sugar binding protein Ste2 on Streptomyces sp. 139.

Results: The disruption of ste2 results in the upregulation of transcription of genes within Ebosin biosynthetic gene cluster and a two-fold increase in Ebosin production. RNA sequencing data suggests that the disruption of ste2 results in the decreased utilization of carbon and nitrogen sources, increased sensitivity to oxidative stress, as well as differed strain morphology, all of which have been experimentally proven.

Conclusions: Taken together, Ste2 controls Ebosin yields, aminosugars uptake, sensitivity to oxidative stress, and morphological differentiation of Streptomyces sp. 139.