Complete Biosynthesis of Erythromycin A and Designed Analogs Using E. coli as a Heterologous Host

Abstract

Erythromycin A is a potent antibiotic long-recognized as a therapeutic option for bacterial infections. The soil-dwelling bacterium Saccharopolyspora erythraea natively produces erythromycin A from a 55 kb gene cluster composed of three large polyketide synthase genes (each ~10 kb) and 17 additional genes responsible for deoxysugar biosynthesis, macrolide tailoring, and resistance. In this study, the erythromycin A gene cluster was systematically transferred from S. erythraea to E. coli for reconstituted biosynthesis, with titers reaching 10 mg/l. Polyketide biosynthesis was then modified to allow the production of two erythromycin analogs. Success establishes E. coli as a viable option for the heterologous production of erythromycin A and more broadly as a platform for the directed production of erythromycin analogs.

Metabolic Engineering of Microorganisms for the Production of Natural Compounds

“…[228] Further trials were put to test by replacing a specific domain or module with its counterpart from different organisms (Figure 14a). [207] This hybrid PKS could successfully adopt the reactions from different organisms into the host PKS machinery. In 2001, Rowe et al succeeded in producing a new polyketide by inserting rapamycin module 2 between DEBS module 1 and module 2 (Figure 14b).…”

“…In the case of erythromycin A production, Zhang et al observed that erythromycin B kept accumulating, thus concluded that eryK-encoding an enzyme converting erythromycin B into erythromycin A-needed to be overexpressed. [207] It…”

“…Among various chaperones, GroES/EL have been widely used; they were utilized for the production of erythromycin C, erythromycin D, [210] and also erythromycin A. [207,211] Going back to the epothilone example, EpoD (encoded by 21.8 kb long epoD) was too large to be successfully expressed in E. coli. Therefore, it was split into two separate polypeptides, both of which were attached with peptide linkers to enhance the protein-protein interaction.…”

“…Total production of erythromycin A-first achieved by Zhang et al-requires a large number of genes, including three large type I PKS genes each spanning more than 10 kb long and 17 additional genes encoding tailoring enzymes. [207] Therefore, the research group used 6 vectors for distributing the genes instead of constructing "super-large" plasmids. Consequently, they were able to produce 0.6 mg L −1 of erythromycin A de novo.…”

Systems metabolic engineering as an enabling technology in accomplishing sustainable development goals

“…Actinomycetes are an important resource for the production of secondary metabolites with various bioactivities including antibiotics, antifungal, anticancer and immunomodulation. SysME has been increasingly employed to allow more efficient design, control and optimization of these secondary metabolites (Weber et al ., 2015), as showcased for erythromycin (Pfeifer et al ., 2001; Zhang et al ., 2010). These achievements have been made possible through large gene cluster cloning (Yuan et al ., 2016), coordinated gene expression optimization (Na et al ., 2013) and genome editing techniques (Wang et al ., 2012) among many other SysME tools developed.…”