title: Tailoring pathway modularity in the biosynthesis of erythromycin analogs heterologously engineered in E. coli.
abstract: Type I modular polyketide synthases are responsible for potent therapeutic compounds that include avermectin (antihelinthic), rapamycin (immunosuppressant), pikromycin (antibiotic), and erythromycin (antibiotic). However, compound access and biosynthetic manipulation are often complicated by properties of native production organisms, prompting an approach (termed heterologous biosynthesis) illustrated in this study through the reconstitution of the erythromycin pathway through Escherichia coli. Using this heterologous system, 16 tailoring pathways were introduced, systematically producing eight chiral pairs of deoxysugar substrates. Successful analog formation for each new pathway emphasizes the remarkable flexibility of downstream enzymes to accommodate molecular variation. Furthermore, analogs resulting from three of the pathways demonstrated bioactivity against an erythromycin-resistant Bacillus subtilis strain. The approach and results support a platform for continued molecular diversification of the tailoring components of this and other complex natural product pathways in a manner that mirrors the modular nature of the upstream megasynthases responsible for aglycone polyketide formation.
authors.affiliation: Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260-4200, USA.
authors.forename: Guojian
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260-4200, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260-4200, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260-4200, USA.
authors.forename: Blaine A
authors.initials: BA
authors.lastname: Pfeifer
keywords: E. coli; Polyketide; analogue; antibiotic; erythromycin; heterologous biosynthesis