杀念菌素/FR-008生物合成途径中转运基因fscTI与fscTII的功能

Function of transporter genes fscTI and fscTII in the biosynthetic cluster of candicidin/FR-008

摘要:

摘要:【目的】分析杀念菌素/FR-008 生物合成途径中转运基因fscTI和fscTII的功能。【方法】构建转运基因fscTI和fscTII的敲除质粒pJTU4137，并通过接合转移和同源重组双交换的方法得到转运基因缺失突变株。转运基因fscTI和fscTII也被克隆到高拷贝质粒pJTU1278上用于在链霉菌FR-008(Streptomyces sp．FR-008)的衍生菌株ZYJ-6中进行转运蛋白的过量表达。【结果】获得了转运蛋白缺失的双交换突变株LX10，发酵结果显示该突变株不再产生杀念菌素及其衍生物;过量表达转运蛋白的基因工程菌株LX11，其杀念菌素的产量约是对照菌株的1.5倍。【结论】体内遗传实验进一步证实FR-008生物合成途径中的fscTI和fscTII是ATP依赖的ABC转运基因，fscTI与fscTII的过量表达增加了杀念菌素的产量，为利用此方法提高其它多烯类抗生素的产量提供了例证。

Abstract:

Abstract:［Objective］ To investigate function of transporter genes fscTI and fscTII in the biosynthetic gene cluster of candicidin/FR-008． ［Methods］We constructed a plasmid pJTU4137 for disruption of transporter genes fscTI and fscTII by conjugation and homologous recombinant． The transporter genes were also PCR amplified and cloned into the high-copy plasmid pJTU1278 for overexpression in strain ZYJ-6 derived from Streptomyces sp. FR-008.［Results］The disruption mutant LX10 was unable to produce candicidin and its analogues． Overexpression of FscTI and FscTII in ZYJ-6 caused a 1.5-fold increase in FR-008-III production compared with the control.［Conclusion］We confirmed that fscTI and fscTII are function as ATP dependent ATP binding cassetle (ABC) transporters in the biosynthetic gene cluster of FR-008. Furthermore，a positive example was provided for improving antibiotic production in other polyene producing strains based on the results that overexpression of fscTI and fscTI increased candicidin production.