Myristoylated recombinant proteins can be synthesized in Escherichia coli by concurrent expression of the enzyme myristoyl-CoA:protein N-myristoyl-transferase with its protein substrates (Duronio, R. J., Jackson-Machelski, E., Heuckeroth, R. O., Olins, P. O., Devine, C. S., Yonemoto, W., Slice, L. W., Taylor, S. S., and Gordon, J. I. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 1506-1510). Expression of the G protein subunit Goα, in this system results in the synthesis of two forms of the protein; these were separated on a column of heptylamine-Sepharose. Purification of the more abundant form of Goα yielded a product that has a blocked amino terminus. Chemical analysis of the fatty acids released by acid hydrolysis of the protein revealed myristic acid. The second form of the protein was not myristoylated. Myristoylated and nonmyristoylated recombinant Goα were compared with brain Goα (which is myristoylated) for their ability to interact with G protein βγ subunits. The nonmyristoylated recombinant protein clearly had a reduced affinity for βγ, while the myristoylated recombinant protein was indistinguishable from native Goα in its subunit interactions. Thus, myristoylation increases the affinity of α subunits for βγ. We propose that the function of myristoylation of G protein α subunits is, at least in part, to facilitate formation of the heterotrimer and the localization of α to the plasma membrane.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|Publication status||Published - Mar 5 1991|
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