Functional and Structural Characterization of 2-Amino-4-phenylthiazole Inhibitors of the HIV-1 Nucleocapsid Protein with Antiviral Activity

Abstract

The nucleocapsid protein (NC) is a highly conserved protein in diverse HIV-1 subtypes that plays a central role in virus replication, mainly by interacting with conserved nucleic acid sequences. NC is considered a highly profitable drug target to inhibit multiple steps in the HIV-1 life cycle with just one compound, a unique property not shown by any of the other antiretroviral classes. However, most of NC inhibitors developed so far act through an unspecific and potentially toxic mechanism (zinc ejection) and are mainly being investigated as topical microbicides. In an effort to provide specific NC inhibitors that compete for the binding of nucleic acids to NC, here we combined molecular modeling, organic synthesis, biophysical studies, NMR spectroscopy, and antiviral assays to design, synthesize, and characterize an efficient NC inhibitor endowed with antiviral activity in vitro, a desirable property for the development of efficient antiretroviral lead compounds.

Identification of novel 2-benzoxazolinone derivatives with specific inhibitory activity against the HIV-1 nucleocapsid protein

“…This initial group of putative ligands was docked by following the same criteria to the receptor structures described above. The process yielded a series of nineteen analogues of compound 5 (named 5-01 to 5-19, Figure 2), which included both benzoxazolinone and benzimidazolinone structures that were able to fit the NC hydrophobic pocket and establish H-bonds with key NC residues [3,12,14,15]. These compounds were further evaluated for their NC inhibition activity.…”

“…A more promising alternative consists of possible competitive inhibitors that may be capable of interfering with the binding of NC to typical nucleic acid substrates [3]. Indeed, it has been shown that the hydrophobic pocket, which forms when the ZF domains are brought close together, for example, by interacting with an exposed guanine nucleobase on cognate nucleic acid substrates, can establish stable interactions with small molecule ligands [12][13][14]. Although such compounds have been touted as possible modulators of NC-nucleic acid interactions, no drug candidate has emerged thus far.…”

NCp7: targeting a multitask protein for next-generation anti-HIV drug development part 2. Noncovalent inhibitors and nucleic acid binders

“…1d-h, these residues are among those involved in NA binding. However, only a residual antiretroviral activity was observed in HIV-1 LAI MAGI cells (EC 50 = 95 mM; CC 50 >250 mM) [25]. In 2012, the developed computational methodologies were used to screen the ASINEX database leading to the identification of ten candidates, in turn tested for their ability to inhibit viral replication through the MAGI assay.…”

Recent Advances in HIV-1 Gag Inhibitor Design and Development

“…The NCI binds in a 2:1 ratio in a hydrophobic pocket, providing π-π stacking interactions with Trp37, thus mimicking the guanosine base of the NC nucleic acid binder. Facilitated by the NMR high-resolution structure, rational optimization in silico resulted in the generation of AN3 (2-amino-4-phenylthiazole NCI), an efficient, non-toxic NCI with antiviral activity in cells [141]. Taken together, these structures provided important insights and supported the drugability of NC towards more improved and efficient drug-like NCIs.…”