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Engineering of methionine chain elongation part of glucoraphanin pathway in E. coli

Paper ID Volume ID Publish Year Pages File Format Full-Text
31491 44803 2016 7 PDF Available
Title
Engineering of methionine chain elongation part of glucoraphanin pathway in E. coli
Abstract

•Chain elongation pathway of glucoraphanin biosynthesis was engineered in E. coli.•25 mg L−1 of dihomo-methionine (precursor to glucoraphanin) was produced.•Methionine supplementation enhanced dihomo-methionine production to 57 mg L−1.•Reconstituted chain elongation machinery in E. coli produced three by-products.

The methionine-derived glucosinolate glucoraphanin is associated with the health-promoting properties of broccoli. This has developed a strong interest in producing this compound in high amounts from a microbial source. Glucoraphanin synthesis starts with a five-gene chain elongation pathway that converts methionine to dihomo-methionine, which is subsequently converted to glucoraphanin by the seven-gene glucosinolate core structure pathway. As dihomo-methionine is the precursor amino acid for glucoraphanin production, a first challenge is to establish an expression system for production of dihomo-methionine. In planta, the methionine chain elongation enzymes are physically separated within the cell with the first enzyme in the cytosol while the rest are located in the chloroplast. A de-compartmentalization approach was applied to produce dihomo-methionine by expression of the respective plant genes in Escherichia coli cytosol. Introduction of two plasmids encoding the methionine chain elongation pathway into E. coli resulted in production of 25 mg L−1 of dihomo-methionine. In addition to chain-elongated methionine products, side-products from chain elongation of leucine were produced. Methionine supplementation enhanced dihomo-methionine production to 57 mg L−1, while keeping a steady level of the chain-elongated leucine products. Engineering of the de-compartmentalized pathway of dihomo-methionine in E. coli cytosol provides an important first step for microbial production of the health-promoting glucoraphanin.

Keywords
HM, Homo-methionine; DHM, dihomo-methionine; HL, homo-leucine; DHL, dihomo-leucine; IPMS, isopropylmalate synthase; MAM, methylthioalkylmalate synthase; BCAT, branched chain amino acid transferase; IPMI-LSU, Arabidopsis isopropylmalate isomerase large sub
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Engineering of methionine chain elongation part of glucoraphanin pathway in E. coli
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 35, May 2016, Pages 31–37
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us