Yoshikuni Yasuo, Dietrich Jeffrey A, Nowroozi Farnaz F, Babbitt Patricia C, Keasling Jay D
UCSF/UCB Joint Graduate Group in Bioengineering, University of California at Berkeley, Berkeley, CA 94720, USA.
Chem Biol. 2008 Jun;15(6):607-18. doi: 10.1016/j.chembiol.2008.05.006.
Nature has balanced most metabolic pathways such that no one enzyme in the pathway controls the flux through that pathway. However, unnatural or nonnative, constructed metabolic pathways may have limited product flux due to unfavorable in vivo properties of one or more enzymes in the pathway. One such example is the mevalonate-based isoprenoid biosynthetic pathway that we previously reconstructed in Escherichia coli. We have used a probable mechanism of adaptive evolution to engineer the in vivo properties of two enzymes (3-hydroxy-3-methylglutaryl-CoA reductase [tHMGR] and many terpene synthases) in this pathway and thereby eliminate or minimize the bottleneck created by these inefficient or nonfunctional enzymes. Here, we demonstrate how we significantly improved the productivity (by approximately 1000 fold) of this reconstructed biosynthetic pathway using this strategy. We anticipate that this strategy will find broad applicability in the functional construction (or reconstruction) of biological pathways in heterologous hosts.
自然界已使大多数代谢途径达到平衡，使得途径中的任何一种酶都无法控制该途径的通量。然而，非天然构建的代谢途径可能因途径中一种或多种酶的体内性质不佳而导致产物通量受限。一个这样的例子是我们之前在大肠杆菌中重建的基于甲羟戊酸的类异戊二烯生物合成途径。我们利用一种可能的适应性进化机制来改造该途径中两种酶（3-羟基-3-甲基戊二酰辅酶A还原酶[tHMGR]和多种萜类合酶）的体内性质，从而消除或最小化由这些低效或无功能的酶造成的瓶颈。在此，我们展示了如何使用该策略显著提高这条重建生物合成途径的产量（约1000倍）。我们预计该策略将在异源宿主中生物途径的功能构建（或重建）中得到广泛应用。
