Potent leads based on CA-19L, an anti-HIV active HIV-1 capsid fragment

Low-molecular-weight anti-HIV-1 agents targeting HIV-1 capsid proteins

The HIV-1 capsid is a shell that encapsulates viral RNA, and forms a conical structure by assembling oligomers of capsid (CA) proteins. Since the CA proteins are highly conserved among many strains of HIV-1, the inhibition of the CA function could be an appropriate goal for suppression of HIV-1 replication, but to date, no drug targeting CA has been developed. Hydrophobic interactions between two CA molecules through Trp184 and Met185 in the protein are known to be indispensable for conformational stabilization of the CA multimer. In our previous study, a small molecule designed by in silico screening as a dipeptide mimic of Trp184 and Met185 in the interaction site was synthesized and found to have significant anti-HIV-1 activity. In the present study, molecules with different scaffolds based on a dipeptide mimic of Trp184 and Met185 have been designed and synthesized. Their significant anti-HIV activity and their advantages compared to the previous compounds were examined. The present results should be useful in the design of novel CA-targeting anti-HIV agents.

Hybrids of small CD4 mimics and gp41-related peptides as dual-target HIV entry inhibitors

Hybrid molecules containing small CD4 mimics and gp41-C-terminal heptad repeat (CHR)-related peptides have been developed. A YIR-821 derivative was adopted as a CD4 mimic, which inhibits the interaction of gp120 with CD4. SC-peptides, SC34 and SC22EK, were also used as CHR-related peptides, which inhibit the interaction between the N-terminal heptad repeat (NHR) and CHR and thereby membrane fusion. Therefore, these hybrid molecules have dual-targets of gp120 and gp41. In the synthesis of the hybrid molecules of CD4 mimic-SC-peptides with different lengths of linkers, two conjugating methods, Cu-catalyzed azide-alkyne cycloaddition and direct cysteine alkylation, were performed. The latter reaction caused simpler operation procedures and higher synthetic yields than the former. The synthesized hybrid molecules of CD4 mimic-SC22EK have significantly higher anti-HIV activity than each sole agent. The present data should be useful in the future design of anti-HIV agents as dual-target entry inhibitors.

An insight on medicinal aspects of novel HIV-1 capsid protein inhibitors

A capsid is the protein shell of a virus, encircling its genetic material. The HIV capsid is erected from a single protein, known as capsid protein. The capsid of HIV-1 significantly involved in many processes of the virus life cycle, which makes it as a novel target for the new inhibitors. Recently many novel HIV-1 inhibitors binding to capsid proteins have been reported successfully. Most of these inhibitors can inhibit or accelerate the disassembly or assembly of the capsid, and some of them can inhibit reverse transcription. Unfortunately, none of them are currently approved by U.S. FDA. However, GS-6207, an inhibitor binds to the NTD-CTD interface with potent antiviral activity and the long metabolic cycle, is expected to be the first approved drug targeting HIV-1 capsid. Herein, we provide a concise report focusing on the recent prospective of HIV-1 capsid inhibitors in medicinal chemistry in order to enlighten drug design.