波卓霉素生物合成基因簇的异源表达及产量提高
Heterologous expression of bottromycin biosynthetic gene cluster and increase of yield

波卓霉素是从波卓链霉菌（Streptomyces bottropensis）中分离得到的，具有抗革兰氏阳性菌及支原体的生物活性，尤其重要的是对耐甲氧西林金黄色葡萄球菌和抗万古霉素肠球菌有抑菌活性。试验通过构建基因组文库，PCR筛选获得包含完整波卓霉素合成基因簇的柯斯质粒4E11，通过接合转移的方法把4E11转化至天蓝色链霉菌M145中，对获得的异源表达株M145/4E11进行发酵，通过提取纯化和HPLC-MS检测，表明M145/4E11发酵液中产生了波卓霉素；试验并通过Red/ET重组系统，以红霉素启动子（ermE*P1）替换了波卓霉素生物合成簇抗性基因btmA和前提肽合成基因btmD的启动子，成功实现异源表达株M145/4E11波卓霉素的产量提高。
Bottromycin with the biological activity against Gram-positive bacteria and mycoplasma was isolated from Streptomyces bottropensis.It exhibited activities against methicillin sensitive Staphylococcus aureus (MRSA) and Vancomycin-Resistant Enterococcus (VRE).Cosmid 4E11 carrying the whole biosynthetic gene cluster of bottromycin was obtained by constructing genomic library and PCR screening,and then transformed into Streptomyces coelicolor M145 by intergeneric conjugation.The recombinant strain M145/4E11 was obtained.The results of fermentation showed that the M145/4E11 could produce bottromycin.Based on the Red/ET recombination system and technology,the native promoters of btmA and btmD were replaced by erythromycin promoter (ermE*P1) in M145/4E11,and bottromycin yield of the mutant was increased successfully.