The recombinant plasmid pMD-ORF2 was digested with EcoR V and Xhol I and then the fragment was sub-cloned into the prokaryotic expressing vector pET-32a(+), getting the recombinant plasmid pET-ORF2.

• 将重组质粒pMD-ORF2的EcoR V和Xhol I双酶切产物亚克隆到原核表达载体pET-32a(+)，构建ORF2基因重组表达质粒pET-ORF2。