Details

Autor(en) / Beteiligte

• Falls, Kelly C
• Williams, Aimee L
• Bryksin, Anton V
• Matsumura, Ichiro
• Cirino, Patrick C.

Titel

Escherichia coli deletion mutants illuminate trade-offs between growth rate and flux through a foreign anabolic pathway

Ist Teil von

• PloS one, 2014-02, Vol.9 (2), p.e88159

Ort / Verlag

United States: Public Library of Science

Erscheinungsjahr

2014

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Metabolic engineers strive to improve the production yields of microbial fermentations, sometimes by mutating the genomes of production strains. Some mutations are detrimental to the health of the organism, so a quantitative and mechanistic understanding of the trade-offs could inform better designs. We employed the bacterial luciferase operon (luxABCDE), which uses ubiquitous energetic cofactors (NADPH, ATP, FMNH2, acetyl-CoA) from the host cell, as a proxy for a novel anabolic pathway. The strains in the Escherichia coli Keio collection, each of which contains a single deletion of a non-essential gene, represent mutational choices that an engineer might make to optimize fermentation yields. The Keio strains and the parental BW25113 strain were transformed with a luxABCDE expression vector. Each transformant was propagated in defined M9 medium at 37 °C for 48 hours; the cell density (optical density at 600 nanometers, OD600) and luminescence were measured every 30 minutes. The trade-offs were visualized by plotting the maximum growth rate and luminescence/OD600 of each transformant across a "production possibility frontier". Our results show that some loss-of-function mutations enhance growth in vitro or light production, but that improvement in one trait generally comes at the expense of the other.