Department of Chemistry and Biochemistry , The University of Texas at El Paso , 500 West University Avenue , El Paso , Texas 79968 , United States.
Department of Biological Sciences , National University of Singapore , 117543 Singapore.
ACS Chem Biol. 2018 Nov 16;13(11):3072-3077. doi: 10.1021/acschembio.8b00896. Epub 2018 Oct 24.
During polyketide and fatty acid biosynthesis, the growing acyl chain is attached to the acyl carrier protein via a thioester linkage. The acyl carrier protein interacts with other enzymes that perform chain elongation and chain modification on the bound acyl chain. Most type I polyketide synthases and fatty acid synthases contain only one acyl carrier protein. However, polyunsaturated fatty acid synthases from deep-sea bacteria contain anywhere from two to nine acyl carrier proteins. Recent studies have shown that this tandem acyl carrier protein feature is responsible for the unusually high fatty acid production rate of deep-sea bacteria. To investigate if a similar strategy can be used to increase the production rate of type I polyketide synthases, a 3×ACP domain was rationally designed and genetically installed in module 6 of 6-deoxyerythronolide B synthase, which is a prototypical type I modular polyketide synthase that naturally harbors just one acyl carrier protein. This modification resulted in an ∼2.5-fold increase in the total amount of polyketide produced in vitro, demonstrating that installing a tandem acyl carrier domain in a type I polyketide synthase is an effective strategy for enhancing the rate of polyketide natural product biosynthesis.
在聚酮和脂肪酸生物合成过程中，不断增长的酰基链通过硫酯键连接到酰基载体蛋白上。酰基载体蛋白与其他酶相互作用，这些酶在结合的酰基链上进行链延伸和链修饰。大多数 I 型聚酮合酶和脂肪酸合酶只含有一个酰基载体蛋白。然而，深海细菌中的多不饱和脂肪酸合酶含有 2 到 9 个酰基载体蛋白。最近的研究表明，这种串联酰基载体蛋白特征是深海细菌具有异常高的脂肪酸产生率的原因。为了研究是否可以使用类似的策略来提高 I 型聚酮合酶的产率，我们合理设计并在 6-脱氧赤藓醇 B 合酶的模块 6 中遗传安装了一个 3×ACP 结构域，6-脱氧赤藓醇 B 合酶是一种典型的 I 型模块化聚酮合酶，天然只含有一个酰基载体蛋白。这一修饰导致体外产生的聚酮总量增加了约 2.5 倍，证明在 I 型聚酮合酶中安装串联酰基载体结构域是提高聚酮天然产物生物合成速率的有效策略。
