Bai Linquan, Li Lei, Xu Hui, Minagawa Kazuyuki, Yu Yi, Zhang Yirong, Zhou Xiufen, Floss Heinz G, Mahmud Taifo, Deng Zixin
Laboratory of Microbial Metabolism and School of Life Science & Biotechnology, Shanghai Jiaotong University, Shanghai 200030, China.
Chem Biol. 2006 Apr;13(4):387-97. doi: 10.1016/j.chembiol.2006.02.002.
A 45 kb DNA sequencing analysis from Streptomyces hygroscopicus 5008 involved in validamycin A (VAL-A) biosynthesis revealed 16 structural genes, 2 regulatory genes, 5 genes related transport, transposition/integration or tellurium resistance; another 4 genes had no obvious identity. The VAL-A biosynthetic pathway was proposed, with assignment of the required genetic functions confined to the sequenced region. A cluster of eight reassembled genes was found to support VAL-A synthesis in a heterologous host, S. lividans 1326. In vivo inactivation of the putative glycosyltransferase gene (valG) abolished the final attachment of glucose for VAL production and resulted in accumulation of the VAL-A precursor, validoxylamine, while the normal production of VAL-A could be restored by complementation with valG. The role of valG in the glycosylation of validoxylamine to VAL-A was demonstrated in vitro by enzymatic assay.
对参与井冈霉素A(VAL-A)生物合成的吸水链霉菌5008进行的45 kb DNA测序分析揭示了16个结构基因、2个调控基因、5个与转运、转座/整合或碲抗性相关的基因;另外4个基因没有明显的同源性。提出了VAL-A生物合成途径,所需的遗传功能被定位到测序区域。发现一组八个重新组装的基因在异源宿主变铅青链霉菌1326中支持VAL-A的合成。推定的糖基转移酶基因(valG)的体内失活消除了VAL生产中葡萄糖的最终附着,并导致VAL-A前体井冈霉胺的积累,而通过用valG互补可以恢复VAL-A的正常生产。通过酶促测定在体外证明了valG在井冈霉胺糖基化形成VAL-A中的作用。