N-lauroylation during the expression of recombinant N- myristoylated proteins: implications and solutions

Abstract

Incorporation of myristic acid to the N-terminus of proteins is a crucial modification that promotes membrane binding and proper localization of important components of signaling pathways. Recombinant expression of N-myristoylatyed proteins in E. coli can be achieved by co-expressing yeast N-myristoyltransferase and supplementing the growth medium with myristic acid. However, undesired incorporation of the 12-carbon fatty acid lauric acid can occur (leading to heterogeneous samples), especially when the available carbon sources are scarce, as it is the case in minimal medium for the expression of isotopically enriched samples. By applying this method to the Brain-acid soluble protein 1 and the 1- 185 N-terminal region of c-Src, we show the significant, and protein- specific, differences in the membrane binding properties of lauroylated and myristoylated forms. We also present a robust strategy for obtaining lauryl free-samples of myristoylated proteins in both rich and minimal media.