The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of anti-retrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidyl-anthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains. We show here that the non-natural linker configuration imparted unexpected TAR RNA targeting properties to the 2,6-peptidyl-anthraquinones and significantly enhanced their potency. Even if the new compounds were able to interact directly with the NC protein, they manifested a consistently higher affinity for the TAR RNA substrate and their TAR-binding properties mirrored their ability to interfere with NC-TAR interactions. Based on these findings, we propose that the viral Tat protein, sharing the same RNA substrate but acting in distinct phases of the viral life cycle, constitutes an additional druggable target for this class of peptidyl-anthraquinones. The inhibition of Tat-TAR interaction for the test compounds correlated again with their TAR-binding properties, while simultaneously failing to demonstrate any direct Tat-binding capabilities. These considerations highlighted the importance of TAR RNA in the elucidation of their inhibition mechanism, rather than direct protein inhibition. We have therefore identified anti-TAR compounds with dual in vitro inhibitory activity on different viral proteins, demonstrating that it is possible to develop multitarget compounds capable of interfering with processes mediated by the interactions of this essential RNA domain of HIV-1 genome with NC and Tat proteins.
HIV-1 核苷酸蛋白(NC)是开发抗逆转录病毒药物的绝佳分子靶标,因为它具有特性良好的伴侣活性,在病毒生命周期的关键步骤中发挥着举足轻重的作用。我们一直在寻找能够损害 NC 结合/退火活动的候选药物,结果发现肽基
蒽醌是一类很有前景的核酸
配体。为了阐明抑制决定因素并提高这类化合物的效力,我们现在探索了连接平面核与碱性侧链的连接体中手性的影响。我们在此表明,非天然连接体构型赋予了 2,6-肽基
蒽醌类化合物意想不到的 TAR RNA 靶向特性,并显著增强了它们的效力。即使新化合物能够直接与 NC 蛋白相互作用,它们对 TAR RNA 底物的亲和力也一直较高,其 TAR 结合特性反映了它们干扰 NC-TAR 相互作用的能力。基于这些发现,我们认为病毒 TAt 蛋白具有相同的 RNA 底物,但在病毒生命周期的不同阶段起作用,是这类肽基
蒽醌类药物的另一个可治疗靶点。测试化合物对 TAt-TAR 相互作用的抑制作用再次与它们的 TAR 结合特性相关,同时也未能证明它们具有任何直接结合 TAt 的能力。这些考虑突出了 TAR RNA 在阐明其抑制机制方面的重要性,而不是直接抑制蛋白质。因此,我们发现了对不同病毒蛋白具有双重体外抑制活性的抗 TAR 化合物,这表明我们有可能开发出能够干扰 HIV-1
基因组中这一重要 RNA 结构域与 NC 和 TAt 蛋白相互作用过程的多靶点化合物。