King Zachary A, Feist Adam M
Department of Bioengineering, University of California, 9500 Gilman Drive #0412, San Diego, La Jolla, CA 92093-0412, USA.
Department of Bioengineering, University of California, 9500 Gilman Drive #0412, San Diego, La Jolla, CA 92093-0412, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark.
Metab Eng. 2014 Jul;24:117-28. doi: 10.1016/j.ymben.2014.05.009. Epub 2014 May 14.
Maintaining cofactor balance is a critical function in microorganisms, but often the native cofactor balance does not match the needs of an engineered metabolic flux state. Here, an optimization procedure is utilized to identify optimal cofactor-specificity "swaps" for oxidoreductase enzymes utilizing NAD(H) or NADP(H) in the genome-scale metabolic models of Escherichia coli and Saccharomyces cerevisiae. The theoretical yields of all native carbon-containing molecules are considered, as well as theoretical yields of twelve heterologous production pathways in E. coli. Swapping the cofactor specificity of central metabolic enzymes (especially GAPD and ALCD2x) is shown to increase NADPH production and increase theoretical yields for native products in E. coli and yeast--including L-aspartate, L-lysine, L-isoleucine, L-proline, L-serine, and putrescine--and non-native products in E. coli-including 1,3-propanediol, 3-hydroxybutyrate, 3-hydroxypropanoate, 3-hydroxyvalerate, and styrene.
维持辅因子平衡是微生物的一项关键功能，但天然的辅因子平衡往往与工程化代谢通量状态的需求不匹配。在此，利用一种优化程序在大肠杆菌和酿酒酵母的基因组规模代谢模型中，为利用NAD(H)或NADP(H)的氧化还原酶确定最佳的辅因子特异性“交换”。考虑了所有天然含碳分子的理论产量，以及大肠杆菌中十二条异源生产途径的理论产量。结果表明，交换中心代谢酶（特别是甘油醛-3-磷酸脱氢酶和苹果酸酶2x）的辅因子特异性可增加NADPH的产生，并提高大肠杆菌和酵母中天然产物（包括L-天冬氨酸、L-赖氨酸、L-异亮氨酸、L-脯氨酸、L-丝氨酸和腐胺）以及大肠杆菌中非天然产物（包括1,3-丙二醇、3-羟基丁酸、3-羟基丙酸、3-羟基戊酸和苯乙烯）的理论产量。
