title: Improved production of L-threonine in Escherichia coli by use of a DNA scaffold system.
abstract: Despite numerous approaches for the development of l-threonine-producing strains, strain development is still hampered by the intrinsic inefficiency of metabolic reactions caused by simple diffusion and random collisions of enzymes and metabolites. A scaffold system, which can promote the proximity of metabolic enzymes and increase the local concentration of intermediates, was reported to be one of the most promising solutions. Here, we report an improvement in l-threonine production in Escherichia coli using a DNA scaffold system, in which a zinc finger protein serves as an adapter for the site-specific binding of each enzyme involved in l-threonine production to a precisely ordered location on a DNA double helix to increase the proximity of enzymes and the local concentration of metabolites to maximize production. The optimized DNA scaffold system for l-threonine production significantly increased the efficiency of the threonine biosynthetic pathway in E. coli, substantially reducing the production time for l-threonine (by over 50%). In addition, this DNA scaffold system enhanced the growth rate of the host strain by reducing the intracellular concentration of toxic intermediates, such as homoserine. Our DNA scaffold system can be used as a platform technology for the construction and optimization of artificial metabolic pathways as well as for the production of many useful biomaterials.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.
authors.forename: Jun Hyoung
authors.initials: JH
authors.lastname: Lee
authors.forename: Suk-Chae
authors.initials: SC
authors.lastname: Jung
authors.forename: Le Minh
authors.initials: le M
authors.lastname: Bui
authors.forename: Kui Hyeon
authors.initials: KH
authors.lastname: Kang
authors.forename: Ji-Joon
authors.initials: JJ
authors.lastname: Song
authors.forename: Sun Chang
authors.initials: SC
authors.lastname: Kim
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances; D060847:Metabolic Engineering; D009097:Multienzyme Complexes; D011485:Protein Binding; D013912:Threonine / Q000096:biosynthesis*; D016335:Zinc Fingers
chemical_list: D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D013912:Threonine; D004247:DNA