High Production of Ergothioneine in Escherichia coli using the Sulfoxide Synthase from Methylobacterium strains

Abstract

We previously constructed a heterologous production system for ergothioneine (ERG) in Escherichia coli using five ERG biosynthesis genes (egtABCDE) from Mycobacterium smegmatis.However, significant amounts of hercynine (HER), an intermediate of ERG, as ERG was accumulated, suggesting that the reaction of EgtB catalyzing the attachment of γ-glutamylcysteine to HER to yield hercynyl-γ-glutamylcysteine sulfoxide was a bottleneck. In this study, we searched for other EgtBs and found many egtB orthologs in diverse microorganisms. Among these, Methylobacterium strains possessed EgtBs that catalyze direct conversion of HER into hercynylcysteine sulfoxide with L-Cys as a sulfur donor, in a manner similar to those of acidobacterial CthEgtB and fungal Egt1. In vitro study with recombinant EgtBs from Methylobacterium brachiatum and M. pseudosasicola clearly showed that both enzymes accepted L-Cys but not γ-glutamylcysteine. We reconstituted the ERG production system in E. coli with egtB from M. pseudosasicola; ERG productivity reached 657 mg L -1 .

Engineering Mycolicibacterium neoaurum for the production of antioxidant ergothioneine

“…EGT is a powerful antioxidant with cytoprotective effects (Ames, 2018;Cheah & Halliwell, 2012). The reconstruction of the EGT synthesis pathway in the commonly used heterogenous biological chassis is a promising strategy (Kamide et al, 2020;Tanaka et al, 2019;van der Hoek et al, 2019), whereas integrating numerous exogenous genes into the host chromosome while maintaining the stability of cell growth and production is still a challenge (Li et al, 2017;Manderscheid et al, 2016), especially the integration of several genes by plasmid vectors (Kamide et al, 2020). Hence, in this study, we mined the production potential of the natural EGT-producing M. neoaurum and described an engineering strategy for the gradual enhancement of EGT production.…”

“…In recent years, the continuous upgrading of synthetic biology toolkits has provided promising solutions for the heterologous synthesis of EGT. To date, several representative strains have been engineered for the heterologous biosynthesis of EGT (Kamide et al, 2020;Kim et al, 2022;Takusagawa et al, 2019;Tanaka et al, 2019;van der Hoek et al, 2019van der Hoek et al, , 2021van der Hoek et al, , 2022. The highest production of EGT (2.39 ± 0.08 g/L) was achieved in 160 h in the engineered Saccharomyces cerevisiae in fedbatch fermentation without supplementation of amino acids (van der Hoek et al, 2022).…”

Ergothioneine, recent developments

“…Other groups have enhanced biosynthesis by recombinantly enhancing copy numbers of the ET biosynthesis genes and enhancing the histidine precursor availability (by removing histidine ammonia-lyase) in Methylobacterium [ 162 ]. Other methods have also been utilized to harness synthetic biology to produce ET and scale up its production using a range of bacterial and fungal microorganisms [ 151 , 152 , 161 , 163 ] and even to generate isotopically labelled variants of ET for research [ 164 ].…”

Recent Strategies for the Biosynthesis of Ergothioneine

“…Further analysis of the production system showed that the accumulation of hercynine, the intermediate of EGT, was an important bottleneck affecting synthesis. By using egtB from Methylobacterium , l -cysteine was used as substrate instead of γ-glutamylcysteine, and the EGT yield reached 657 mg/L . The three precursor amino acids, l -cysteine, l -histidine, and l -methionine, that directly affect the synthesis of EGT are relatively low for overproduction to be performed; thus, it is necessary to enhance the flux of EGT biosynthesis through metabolic engineering.…”

“…By using egtB from Methylobacterium, Lcysteine was used as substrate instead of γ-glutamylcysteine, and the EGT yield reached 657 mg/L. 44 The three precursor amino acids, L-cysteine, L-histidine, and L-methionine, that directly affect the synthesis of EGT are relatively low for overproduction to be performed; thus, it is necessary to enhance the flux of EGT biosynthesis through metabolic engineering. Tanaka et al reported that 1.31 g/L EGT was successfully produced by overexpressing egtA, introducing egtBCDE from M. smegmatis, and knocking out metJ, a transcriptional inhibitor of Met metabolism, in E. coli cells with high Cys production.…”