嗜热菌XZ2K2葡聚糖蔗糖酶基因的克隆与表达

Cloning and Expression of Dextransucrase Gene from Thermophile Bacteria XZ2K2

提取嗜热菌XZ2K2的基因组DNA。通过对基因库中葡聚糖蔗糖酶基因序列进行分析比较,设计了两对引物。通过构建基因组文库,进行PCR筛选,扩增出4.5 kb的同源片段。DNA序列分析表明,该片段与已经报道的葡聚糖蔗糖酶编码基因(dex基因)具有90%的同源。将该片段与载体pSE380连接,构建了重组质粒pSE380-dex。然后用化学方法将重组质粒转化到大肠杆菌JM109中,获得重组子pSE380-dex。进一步的实验表明,嗜热菌的dex基因可以在JM109中表达。

A 4.5 kb fragment which was homologous to dex gene encoding gluean was amplified by construeting genomie library and PCR, using conservative sequence of dex gene as primers. The 4.5 kb fragment was sequenced. A open reading frame（ORF） encoded amino acids was identified from this fragment and was shared 90% homology with reported dex gene. One recombinant plasmid, named pSE380-dex was obtained by ligatied the 4.5 kb fragment with pSE380 vector and transformated into E. coli strain JM109. It was shown that this dex gene could be expressed in E. coli strain JM109.