Kato Yasuo, Bai Linquan, Xue Qun, Revill W Peter, Yu Tin-Wein, Floss Heinz G
Department of Chemistry, Box 351700, University of Washington, Seattle, Washington 98195-1700, USA.
J Am Chem Soc. 2002 May 15;124(19):5268-9. doi: 10.1021/ja0127483.
A subcluster of five genes, asm13-17, from the ansamitocin biosynthetic gene cluster of Actinosynnema pretiosum was coexpressed in Streptomyces lividans with the genes encoding the 6-deoxyerythronolide B (6-DEB) synthase from Saccharopolyspora erythraea, in which the methylmalonate-specifying AT6 domain had been replaced by the methoxymalonate-specifying AT8 domain from the FK520 cluster of Streptomyces hygroscopicus. The engineered strain produced the predicted product, 2-desmethyl-2-methoxy-DEB, instead of 6-DEB and 2-desmethyl-6-DEB, which were formed in the absence of the asm13-17 cassette, indicating that asm13-17 are sufficient for synthesis of this unusual chain extension unit. Deletion of asm17, encoding a methyltransferase, from the cassette gave 6-DEB instead of its hydroxy analogue, indicating that methylation of the extender unit is required for its incorporation.
从美丽放线菌的安丝菌素生物合成基因簇中选取了五个基因（asm13 - 17）组成的一个亚簇，将其与编码来自糖多孢红霉菌的6 - 脱氧红霉内酯B（6 - DEB）合酶的基因在淡紫链霉菌中共表达，其中来自吸水链霉菌FK520基因簇的指定甲氧基丙二酸的AT8结构域取代了指定丙二酸单酰的AT6结构域。该工程菌株产生了预测产物2 - 去甲基 - 2 - 甲氧基 - DEB，而不是在没有asm13 - 17盒时形成的6 - DEB和2 - 去甲基 - 6 - DEB，这表明asm13 - 17足以合成这种不寻常的链延伸单元。从该盒中缺失编码甲基转移酶的asm17后得到的是6 - DEB而非其羟基类似物，这表明延伸单元的甲基化是其掺入所必需的。
