链霉菌质粒pSGL1最小复制子序列测定及分析

NUCLEOTIDE SEQUENCE ANALYSIS OF THE MINIMAL REPLICON OF THE STREPTOMYCES PLASMID pSGL1

质粒ｐＳＧＬ１（７．４ｋｂ）是从球孢链霉菌（Ｓｔｒｅｐｔｏｍｙｃｅｓｇｌｏｂｉｓｐｏｒｕｓ）中分离得到的一个高拷贝质粒，已证明其最小复制子位于Ｓａｕ３ＡＩ酶切的２０ｋｂ片段上。对该片段进行亚克隆，测序后数据表明该片段是一个新序列。仅有一个开放阅读框架（ＯＲＦＲ）位于最小复制子中，推测其编码的蛋白质含有滚环复制质粒复制酶的特定序列。

The high copy number plasmid pSGL1(7.4kb) was isolated from Streptomyces globisporus . Deletion experiments showed its minimal replicon is located on the 2.0kb Sau 3 AI fragment. This fragment was subcloned. DNA sequence data analysis showed this fragment is a new sequence. Only an open reading frame with high coding probability is located on the minimal replicon. The deduced protein contains motifs characteristic of replicase for rolling circle replication.