Synthesis of acridone derivatives via heterologous expression of a plant type III polyketide synthase in Escherichia coli

Abstract

Background: Acridone alkaloids are heterocyclic compounds that exhibit a broad-range of pharmaceutical and chemotherapeutic activities, including anticancer, antiviral, anti-inflammatory, antimalarial, and antimicrobial effects. Certain plant species such as Citrus microcarpa, Ruta graveolens, and Toddaliopsis bremekampii synthesize acridone alkaloids from anthranilate and malonyl-CoA. Results:We synthesized two acridones in Escherichia coli. Acridone synthase (ACS) and anthraniloyl-CoA ligase genes were transformed into E. coli, and the synthesis of acridone was examined. To increase the levels of endogenous anthranilate, we tested several constructs expressing proteins involved in the shikimate pathway and selected the best construct. To boost the supply of malonyl-CoA, genes coding for acetyl-coenzyme A carboxylase (ACC ) from Photorhabdus luminescens were overexpressed in E. coli. For the synthesis of 1,3-dihydroxy-10-methylacridone, we utilized an N-methyltransferase gene (NMT) to supply N-methylanthranilate and a new N-methylanthraniloyl-CoA ligase. After selecting the best combination of genes, approximately 17.3 mg/L of 1,3-dihydroxy-9(10H)-acridone (DHA) and 26.0 mg/L of 1,3-dihydroxy-10-methylacridone (NMA) were synthesized. Conclusions:Two bioactive acridone derivatives were synthesized by expressing type III plant polyketide synthases and other genes in E. coli, which increased the supplement of substrates. This study showed that is possible to synthesize diverse polyketides in E. coli using plant polyketide synthases.

Biosynthesis of ethyl caffeate via caffeoyl-CoA acyltransferase expression in Escherichia coli

“…3). This result agreed with the previous studies in which the overexpression of shikimate gene module increased the final titer of the synthesized compound; however, the best gene-module construct was different depending on the compound synthesized [24,28,29].…”

Engineered biosynthesis of plant polyketides by type III polyketide synthases in microorganisms

“…QNS catalyzes the decarboxylation condensation of starter one N-methylanthraniloyl-CoA and one malonyl-CoA which spontaneously cyclize to 4-hydroxy-1-methyl-2(1H)quinolone. In 2020, Choi et al (2020) constructed E. coli strains to produce 1,3-dihydroxy-9(10H)-acridone (DHA) and 1,3-dihydroxy-10-methylacridone (NMA) de novo. The pathway contains acridone synthase and N-methyltransferase (NMT) from Ruta graveolens, benzoate CoA ligase (badA) from Rhodopseudomonas palustris and anthranilate coenzyme A ligase (pqsA) from Pseudomonas.…”

Fermentative N-Methylanthranilate Production by Engineered Corynebacterium glutamicum

“…In the biosynthesis of acridone alkaloids, e.g., in R. graveolens, N-methylation of anthranilate catalyzed by ANMT is a key step preceding CoA activation and, thus, separating primary metabolism (here tryptophan synthesis) from secondary metabolism [16,19]. Recently, production of about 26 mg•L −1 1,3-dihydroxy−10-methylacridone [65] and about 18 mg•L −1 4-hydroxy-1-methyl-2(1H)-quinolone [66] were established in E. coli coexpressing anmt from R. graveloens, anthranilate coenzyme A ligase from P. aeruginosa, and acridone synthase of R. graveolens or the anthraniloyl-CoA anthraniloyltransferase from P. aeruginosa. In these biosynthesis pathways, one molecule of NMA is required per one molecule 1,3-dihydroxy-10-methylacridone or 4-hydroxy-1-methyl-2(1H)-quinolone [65,66].…”

“…Recently, production of about 26 mg•L −1 1,3-dihydroxy−10-methylacridone [65] and about 18 mg•L −1 4-hydroxy-1-methyl-2(1H)-quinolone [66] were established in E. coli coexpressing anmt from R. graveloens, anthranilate coenzyme A ligase from P. aeruginosa, and acridone synthase of R. graveolens or the anthraniloyl-CoA anthraniloyltransferase from P. aeruginosa. In these biosynthesis pathways, one molecule of NMA is required per one molecule 1,3-dihydroxy-10-methylacridone or 4-hydroxy-1-methyl-2(1H)-quinolone [65,66]. The NMA-producing C. glutamicum strain NMA105 developed here may in the future be used in combination with this engineered E. coli strain, possibly as synthetic consortium [67,68], or C. glutamicum NMA105 itself may be engineered for production of acridone alkaloids.…”