PhoP- and GlnR-mediated regulation of metK transcription and its impact upon S-adenosyl-methionine biosynthesis in Saccharopolyspora erythraea

Abstract

Background Erythromycin A (Er A) has a broad antibacterial effect and is a source of erythromycin derivatives. Methylation of erythromycin C (Er C), catalyzed by S-adenosyl-methionine (SAM)-dependent O-methyltransferase EryG, is the key final step in Er A biosynthesis. Er A biosynthesis, including EryG production, is regulated by the phosphate response factor PhoP and the nitrogen response factor GlnR. However, the regulatory effect of these proteins upon S-adenosyl-methionine synthetase (MetK) production is unknown. Results In this study, we used bioinformatics approaches to identify metK (SACE_3900), which codes for S-adenosyl-methionine synthetase (MetK). Electrophoretic mobility shift assays (EMSAs) revealed that PhoP and GlnR directly interact with the promoter of metK, and quantitative PCR (RT-qPCR) confirmed that each protein positively regulated metK transcription. Moreover, intracellular SAM was increased upon overexpression of either phoP or glnR under phosphate or nitrogen limited conditions, respectively. Finally, both the production of Er A and the transformation ratio from Er C to Er A increased upon phoP overexpression, but surprisingly, not upon glnR overexpression. Conclusions Manipulating the phosphate and nitrogen response factors, PhoP and GlnR provides a novel strategy for increasing the yield of SAM and the production of Er A in Saccharopolyspora erythraea .

Research progress on GlnR-mediated regulation in Actinomycetes

“…In addition, Ye et al demonstrated that PhoP modulates erythromycin biosynthesis in S. erythraea by integrating phosphate/nitrogen signals, governing the interaction between phosphate/nitrogen metabolism and specialized metabolism (Xu et al, 2019). Furthermore, GlnR and PhoP enhance the production of erythromycin by regulating primary metabolism and thus precursors availability (Pei et al, 2022).…”

Metabolomics-assisted mechanism analysis of γ-PGA synthesis regulated by PhoP inB. licheniformis

“…It is worthing noting that PhoP could also affect the expression levels of nitrogen metabolism genes glnR, glnA, glnII and amtB-glnK-glnD operon (Martin et al 2011). Among them, the combined modification of GlnR and PhoP could comprehensively regulate nitrogen and phosphorus metabolisms in S. coelicolor, and participated in the efficient biosynthesis of multiple intermediate and secondary metabolites, such as S-adenosylmethionine (Pei et al 2022) and erythromycin A (Pei et al 2022. The γ-PGA synthesis in B. licheniformis is heavily depending on external nitrogen source, whether PhoP regulates γ-PGA synthesis in Bacillus has not been reported.…”