Expression and purification of 6XHIS-Tagged fusion proteins derived from random peptide phage display in Escherichia coli

Abstract

The gene-expression system was used to overproduce desired peptides derived from six individual phage clones previously selected by MAb 5145A recognizing CD 4 binding sit epitope on HIVgp120. Presenting in the biological context, peptides fused to the N-terminal of filamentous phage were expressed in Escherichia coli. Each gene product was generated as inclusion body and soluble forms. The inclusion bodies were produced maximally at 8 hours, whereas the soluble proteins in the supernatant were generated nearly steadily throughout the time profile. The soluble proteins in supernatant were purified by metal chromatography and preliminarily characterized in terms of binding property to MAb 5145A. It was found that the corresponding MAb compared to the control recognized partially purified proteins. This finding indicated that overproduced peptides could adopt the original conformation that was selected when it was in the context of phage scaffold and probably could mimic the functional image of CD4 binding site epitope on HIVgp120