Reconstitution of protein N-myristoylation in Escherichia coli

A dual-plasmid expression system that coexpresses Saccharomyces cerevisiae myristoyl-CoA:protein N-myristoyltransferase (NMT) and various known mammalian N-myristoylproteins in Escherichia coli is described. Coexpression of these proteins results in efficient N-myristoylation in the bacterium, which has no endogenous NMT activity. N-Myristoylation in E. coli requires that the protein substrate have a Gly² residue, and is specific for 14-carbon fatty acids as in eukaryotes. The system is useful for (i) analyzing NMT structure/activity relationships, (ii) examining the determinants required for efficient N-myristoylation in vivo, and (iii) directly assessing the biological significance of this modification of specific eukaryotic proteins by purifying the corresponding nonmyristoylated and N-myristoylated recombinant forms from E. coli.