链丝菌素生物合成基因簇的克隆及其异源表达

通过基因组粘粒文库的高通量接合转移、异源表达和生物活性测定,结合DNA序列测定,从刺孢吸水链霉菌AA97026中筛选具有广谱抗菌活性的小分子化合物及其生物合成基因簇,获得1个对革兰氏阳性细菌和红酵母均有抑制活性的阳性克隆1H5,其部分DNA序列与链丝菌素生物合成基因相似。含1H5的异源链霉菌宿主的发酵液均能检测到链丝菌素的不同组份,表明1H5含有完整的链丝菌素生物合成基因簇。

Cloning and heterologous expression of a streptothricin biosynthetic gene cluster

To obtain small molecular antibacterial compound and its biosynthetic gene cluster,a genomic cosmid library was screened by high-throughput conjugation,heterologous expression,bioassay,and combined with DNA sequencing.A positive clone 1H5 expressing growth-inhibition activities against gram positive bacteria and Rhodotorula was obtained from the genomic library of Streptomyces hygrospinosus.The cosmid 1H5 harbored a cluster of genes highly similar to previously reported streptothricin biosynthetic gene clusters in terms of sequence and gene organization.Streptothricins were detected in the fermentation broth of Streptomyces expression hosts carrying 1H5,indicating that this clone contained an entire gene cluster for streptothricin biosynthesis.The cloning and heterologous expression of the biosynthetic gene cluster pave the way for further study of the biosynthesis,regulation and structural modification of streptothricin.