Replication of human immunodeficiency virus 1 and Moloney murine leukemia virus is inhibited by different heteroatom-containing analogs of myristic acid

Myristoyl-CoA:protein N-myristoyltransferase (NMT; EC 2.3.1.97) catalyzes the cotranslational linkage of myristate to the N-terminal glycine residues of several cellular, viral, and oncoproteins. We have recently synthesized a series of sulfur- and oxygen-substituted analogs of myristic acid that are similar in length to the 14:0 fatty acid yet have hydrophobicities equivalent to dodecanoate or decanoate. Previous in vitro enzyme assays and metabolic labeling studies indicate that some of these analogs are excellent substrates for NMT and are incorporated into subsets of cellular N-myristoyl proteins. Their sequence-specific incorporation probably arises from cooperative interactions between the acyl CoA and peptide binding sites of NMT. The human immunodeficiency virus 1 (HIV-1) and Moloney murine leukemia virus (MoMLV) depend on myristoylation of gag polyprotein precursors for assembly. We have tested four analogs - 12-methoxydodecanoic acid, 10-propoxydecanoic acid, 5-octyloxypentanoic acid, and 11-ethylthioundecanoic acid - for their ability to block replication of these retro-viruses. All reduce HIV-1 replication when incubated with CD4⁺ H9 cells for 10 days at 10-100 μM. 12-Methoxydodecanoic acid is most effective, producing a concentration-dependent decrease in (i) reverse transcriptase activity (to levels that were 5-10% of control at 20-40 μM), (ii) p24 levels, and (iii) syncytia formation. This degree of inhibition of HIV-1 replication is equivalent to that seen with 5 μM 3'-azido-3'-deoxythymidine and is accomplished without apparent toxicity, as measured by cell viability, protein, and nucleic acid synthesis. 5-Octyloxypentanoic acid inhibits MoMLV assembly in a dose-dependent fashion without accompanying cellular toxicity, while 12-methoxydodecanoic acid has no effect. These data suggest that the use of cellular NMT activity to deliver analogs of myristate with altered physical-chemical properties to proteins that undergo this cotranslational modification may represent an effective antiviral therapeutic strategy as well as a way to investigate the role of covalently bound fatty acid in viral assembly.