Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
J Antibiot (Tokyo). 2011 Jan;64(1):59-64. doi: 10.1038/ja.2010.129. Epub 2010 Nov 17.
Erythromycin and related macrolide antibiotics are widely used polyketide natural products. We have evolved an engineered biosynthetic pathway in Escherichia coli that yields erythromycin analogs from simple synthetic precursors. Multiple rounds of mutagenesis and screening led to the identification of new mutant strains with improved efficiency for precursor-directed biosynthesis. Genetic and biochemical analysis suggested that the phenotypically relevant alterations in these mutant strains were localized exclusively to the host-vector system, and not to the polyketide synthase. We also demonstrate the utility of this improved system through engineered biosynthesis of a novel alkynyl erythromycin derivative with comparable antibacterial activity to its natural counterpart. In addition to reinforcing the power of directed evolution for engineering macrolide biosynthesis, our studies have identified a new lead substance for investigating structure-function relationships in the bacterial ribosome.
红霉素和相关的大环内酯类抗生素是广泛使用的聚酮天然产物。我们在大肠杆菌中设计了一种工程化的生物合成途径，能够从简单的合成前体中产生红霉素类似物。经过多轮诱变和筛选，我们鉴定出了新的突变株，它们在导向前体生物合成方面的效率得到了提高。遗传和生化分析表明，这些突变株中表型相关的改变仅局限于宿主载体系统，而不是聚酮合酶。我们还通过工程化合成具有与其天然对应物相当的抗菌活性的新型炔基红霉素衍生物，证明了该改进系统的实用性。除了增强定向进化在大环内酯类生物合成工程中的力量外，我们的研究还确定了一个新的先导物质，用于研究细菌核糖体的结构-功能关系。
