Improving heterologous polyketide production in Escherichia coli by overexpression of an S-adenosylmethionine synthetase gene.
An S-adenosylmethionine synthetase gene (metK) from Streptomyces spectabilis was cloned into an expression plasmid under the control of an inducible T7 promoter and introduced into a strain of Escherichia coli (BAP1(pBP130/pBP144)) capable of producing the polyketide product 6-deoxyerythronolide B (6-dEB). The metK coexpression in BAP1(pBP130/pBP144) improved the specific production of 6-dEB from 10.86 to 20.08 mg l(-1) OD(600)(-1). In an effort to probe the reason for this improvement, a series of gene deletion and expression experiments were conducted based on a metK metabolic pathway that branches between propionyl-CoA (a 6-dEB precursor) and autoinducer compounds. The deletion and expression studies suggested that the autoinducer pathway had a larger impact on improved 6-dEB biosynthesis. Supporting these results were experiments demonstrating the positive effect conditioned media (the suspected location of the autoinducer compounds) had on 6-dEB production. Taken together, the results of this study show an increase in heterologous 6-dEB production concomitant with heterologous metK gene expression and suggest that the mechanism for this improvement is linked to native autoinducer compounds.
Wang
Yong
Y
Department of Chemical and Biological Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA.
Boghigian
Brett A
BA
Pfeifer
Blaine A
BA
D001709:Biotechnology / Q000379:methods; D003001:Cloning, Molecular; D003470:Culture Media; D004789:Enzyme Activation; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008716:Methionine Adenosyltransferase / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012436:S-Adenosylmethionine / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics; D015854:Up-Regulation
D003470:Culture Media; C034277:6-deoxyerythronolide B; D004917:Erythromycin; D012436:S-Adenosylmethionine; D008716:Methionine Adenosyltransferase