Chemical characterization of p17gag from human immunodeficiency virus as an N-terminally myristoylated protein.

The N-terminal p17gag protein of the human immunodeficiency virus has been shown to incorporate radioactivity following labelling of infected cell lines with [3H]myristic acid. We investigated p17gag to determine whether the incorporated radioactivity was the consequence of N-terminal myristoylation. The virus was purified by density gradient centrifugation after labelling chronically infected H9 cells with [3H]myristic acid. The p17gag was isolated by immunoprecipitation and subjected to partial acid hydrolysis. [3H]Myristoylglycine generated by the hydrolysis was derivatized to 4-(p-nitrobenzylidene)-2-tridecanoyloxazol-5-one and identified against a co-eluting, derivatized, unlabelled N-myristoylglycine standard by reverse-phase high-performance liquid chromatography. This study unequivocally demonstrates that p17gag is an N-myristoylated protein.