Ingénierie enzymatique
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Abstrait

Low Molecular Weight Protein Tyrosine Phosphatases Control Antibiotic Production in Streptomyces coelicolor A3(2)

Sujata Vijay Sohoni, Sarah Lieder, Prashant Bapat, Ivan Mijakovic and Anna Eliasson Lantz

Streptomyces coelicolor A3(2) possesses a low molecular weight protein tyrosine phosphatase (LMW-PTP), PtpA, that affects the production of undecylprodigionsin (RED) and actinorhodin (ACT). In this study we identified another LMW-PTP called sco3700. Tyrosine phosphatase activity of the purified Sco3700 was established using para-nitrophenyl phosphate and the tyrosine-phosphorylated protein PtkA from Bacillus subtilis as substrates. The optimum pH for the Sco3700 phosphatase activity was 6.8, and KM for pNPP was 14.3 mM compared to pH 6.0 and KM0.75 mM for PtpA. The potential of Sco3700 to participate, alongside PtpA, in the regulation of S. coelicolor antibiotic production was investigated. Hence, S. coelicolor A3(2) strains with ptpA and sco3700 overexpression were constructed and characterized for growth, RED and ACT production. We did observe an increase in volumetric productivity of ACT in the ptpA over expression strain. Furthermore, a significantly earlier onset of ACT production was observed when ptpA was over expressed. Sco3700 overexpression had a pleiotropic effect on the cell, and the strain exhibited lower productivities and final concentrations of antibiotics. We conclude that Sco3700 is indeed a tyrosine phosphatase, and it contributes to regulation of antibiotic production in S. coelicolor affecting the timing of onset of the antibiotic production.