Increased solubility of recombinant human nerve growth factor expressed in Escherichia coli AD494 (DE3)

摘要

The coding sequence of 118-amino acid mature human nerve growth factor (NGF) was amplified from human placenta and cloned into pET28a, when E. coli BL21 (DE3) was used as the host strain, the expression level was ～20%, however, all of the recombinant NGF were insoluble judged by SDS-PAGE. In order to improve the solubility, we first replaced the kanamycin resistance gene in the pET28a-NGF expression vector with ampicillin resistance gene using a special DNA recombination system, then the ampicillin resistant pET28a-NGF was introduced into another host strain, E. coli AD494 (DE3) carrying a kanamycin resistance gene on the bacterial genome. Under the same growth condition, the NGF expression level in E. coli AD494 (DE3) was similar as in E. coli BL21 (DE3), but the soluble recombinant protein represented ～30% of the recombinant protein as shown by SDS-PAGE.