MacNeil D J, Occi J L, Gewain K M, MacNeil T, Gibbons P H, Ruby C L, Danis S J
Department of Microbial Chemotherapeutics and Molecular Genetics, Merck Sharp & Dohme Research Laboratories, Rahway, NJ 07065.
Gene. 1992 Jun 15;115(1-2):119-25. doi: 10.1016/0378-1119(92)90549-5.
The avermectin (Av) polyketide synthase (PKS) and erythromycin (Er) PKS are encoded by modular repeats of DNA, but the genetic organization of the modules encoding Av PKS is more complex than Er PKS. Sequencing of several related DNA fragments from Streptomyces avermitilis that are part of the Av biosynthetic gene cluster, revealed that they encode parts of large multifunctional PKS proteins. The Av PKS proteins show strong similarity to each other, as well as similarity to Er PKS proteins [Donadio et al., Science 252 (1991) 675-679] and fatty acid synthases. Partial DNA sequencing of the 65-kb region containing all the related sequence elements in the avr genes provides evidence for twelve modular repeats encoding FAS-like domains. The genes encoding the Av PKS are organized as two sets of six modular repeats which are convergently transcribed.
阿维菌素（Av）聚酮合酶（PKS）和红霉素（Er）聚酮合酶由DNA的模块化重复序列编码，但编码Av聚酮合酶的模块的遗传组织比Er聚酮合酶更复杂。对来自阿维链霉菌的几个与Av生物合成基因簇相关的DNA片段进行测序，结果表明它们编码大型多功能聚酮合酶蛋白的部分序列。Av聚酮合酶蛋白彼此之间表现出很强的相似性，同时也与Er聚酮合酶蛋白[多纳迪奥等人，《科学》252（1991）675 - 679]以及脂肪酸合酶相似。对包含avr基因中所有相关序列元件的65 kb区域进行部分DNA测序，为编码类脂肪酸合酶结构域的十二个模块化重复序列提供了证据。编码Av聚酮合酶的基因被组织成两组，每组六个模块化重复序列，它们以反向转录的方式排列。
