The choEW was inserted into prokaryotic expression vector pET-His, and the resulting recombinant plasmid pETW was used to transform E. colt BL21(DE3)plysS.

• 将choEW插入到原核表达载体pET-His中,构建出重组质粒pETW,并转化Escherichia coli BL21(DE3)plysS获得工程菌。