کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6452768 | 1418339 | 2017 | 9 صفحه PDF | دانلود رایگان |
- SACE_Lrp negatively regulates erythromycin production in Saccharopolyspora erythraea.
- SACE_Lrp directly regulates the BCAA transport and indirectly regulates the BCAA catabolism in S. erythraea.
- SACE_Lrp is the first reported Lrp showing two-directional response to its amino acid-effectors.
- A high erythromycin-producing strain has been constructed by engineering the SACE_Lrp regulatory elements.
Leucine-responsive regulatory proteins (Lrps) are a group of transcriptional regulators that regulate diverse cellular processes in bacteria and archaea. However, the regulatory role of Lrps in antibiotic biosynthesis remains poorly understood. In this study, we show that SACE_5388, an Lrp family regulator named as SACE_Lrp, is an efficient regulator for transporting and catabolizing branched-chain amino acids (BCAAs), playing an important role in regulating erythromycin production in Saccharopolyspora erythraea. SACE_Lrp directly controlled the expression of the divergently transcribed SACE_5387-5386 operon putatively encoding a BCAA ABC transporter by interacting with the intergenic region between SACE_Lrp and SACE_5387 (SACE_Lrp-5387-int), and indirectly controlled the expression of ilvE putatively encoding an aminotransferase catabolizing BCAAs. BCAA catabolism is one source of the precursors for erythromycin biosynthesis. Lysine and arginine promoted the dissociation of SACE_Lrp from SACE_Lrp -5387-int, whereas histidine increased their binding. Gene disruption of SACE_Lrp (ÎSACE_Lrp) in S. erythraea A226 resulted in a 25% increase in erythromycin production, while overexpression of SACE_5387-5386 in A226 enhanced erythromycin production by 36%. Deletion of SACE_Lrp (WBÎSACE_Lrp) in the industrial strain S. erythraea WB enhanced erythromycin production by 19%, and overexpression of SACE_5387-5386 in WBÎSACE_Lrp (WBÎSACE_Lrp/5387-5386) increased erythromycin production by 41% compared to WB. Additionally, supplement of 10Â mM valine to WBÎSACE_Lrp/5387-5386 culture further increased total erythromycin production up to 48%. In a 5-L fermenter, the erythromycin accumulation in the engineered strain WBÎSACE_Lrp/5387-5386 with 10Â mM extra valine in the industrial culture media reached 5001Â mg/L, a 41% increase over 3503Â mg/L of WB. These insights into the molecular regulation of antibiotic biosynthesis by SACE_Lrp in S. erythraea are instrumental in increasing industrial production of secondary metabolites.
Journal: Metabolic Engineering - Volume 39, January 2017, Pages 29-37