Expression of membrane proteins in Escherichia coli as fusions to the phage phi6 major envelope protein

Abstract

A large portion of an organism's proteome comprises membrane proteins; these prtteins are physiologically important and are often major drug targets. Despite eliciting substantial academic interest and having great economic importance, current understanding of the structures and functions of membrane proteins lags behind that of soluble proteins. One of the major reasons for this delay is the difficulty associated with producing membrane proteins in large quantities. In fact, bacterial expression of membrane proteins remains a major challenge in recombinant DNA technology. Here, we report the use of the major envelope protein (P9) of bacteriophage phi6 as a fusion partner for successful expression of bacterial membrane proteins in Escherichia coli. Of the ten membrane proteins included in the study, eight were produced in an intact form in large quantities. One protein degraded and one was not expressed at all. All of the proteins examined in this study contained more than eight trans membrane segments. Future work will focus on the purification of these overproduced proteins and verification of their biological functions.