Qi Zhi, Shi Weiguo, Xue Na, Pan Chungen, Jing Weiguo, Liu Keliang, Jiang Shibo
Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York 10065, USA.
J Biol Chem. 2008 Oct 31;283(44):30376-84. doi: 10.1074/jbc.M804672200. Epub 2008 Jul 28.
We have previously shown that the first generation human immunodeficiency virus (HIV) fusion inhibitor T20 (Fuzeon) contains a critical lipid-binding domain (LBD), whereas C34, another anti-HIV peptide derived from the gp41 C-terminal heptad repeat, consists of an important pocket-binding domain (PBD), and both share a common 4-3 heptad repeat (HR) sequence (Liu, S., Jing, W., Cheung, B., Lu, H., Sun, J., Yan, X., Niu, J., Farmar, J., Wu, S., and Jiang, S. (2007) J. Biol. Chem. 282, 9612-9620). T1249, the second generation HIV fusion inhibitor, has both LBD and PBD but a different HR sequence, suggesting that these three anti-HIV peptides may have distinct mechanisms of action. Here we rationally designed a set of peptides that contain multiple copies of a predicted HR sequence (5HR) or the HR sequence plus either LBD (4HR-LBD) or PBD (PBD-4HR) or both (PBD-3HR-LBD), and we compared their anti-HIV-1 activity and biophysical properties. We found that the peptide 5HR exhibited low-to-moderate inhibitory activity on HIV-1-mediated cell-cell fusion, whereas addition of LBD and/or PBD to the HR sequence resulted in a significant increase of the anti-HIV-1 activity. The peptides containing PBD, including PBD-4HR and PBD-3HR-LBD, could form a stable six-helix bundle with the N-peptide N46 and effectively blocked the gp41 core formation, whereas the peptides containing LBD, e.g. 4HR-LBD and PBD-3HR-LBD, could interact with the lipid vehicles. These results suggest that the HR sequence in these anti-HIV peptides acts as a structure domain and is responsible for its interaction with the HR sequence in N-terminal heptad repeat, whereas PBD and LBD are critical for interactions with their corresponding targets. T20, C34, and T1249 may function like 4HR-LBD, PBD-4HR, and PBD-3HR-LBD, respectively, to interact with different target sites for inhibiting HIV fusion and entry. Therefore, this study provides important information for understanding the mechanisms of action of the peptic HIV-1 fusion inhibitors and for rational design of novel antiviral peptides against HIV and other viruses with class I fusion proteins.
我们之前已经表明，第一代人类免疫缺陷病毒（HIV）融合抑制剂T20（福泽昂）包含一个关键的脂质结合结构域（LBD），而另一种源自gp41 C末端七肽重复序列的抗HIV肽C34则由一个重要的口袋结合结构域（PBD）组成，并且两者都共享一个共同的4-3七肽重复（HR）序列（Liu, S., Jing, W., Cheung, B., Lu, H., Sun, J., Yan, X., Niu, J., Farmar, J., Wu, S., and Jiang, S. (2007) J. Biol. Chem. 282, 9612 - 9620）。第二代HIV融合抑制剂T1249同时具有LBD和PBD，但HR序列不同，这表明这三种抗HIV肽可能具有不同的作用机制。在此，我们合理设计了一组肽，它们包含预测的HR序列（5HR）的多个拷贝，或者HR序列加上LBD（4HR-LBD）或PBD（PBD-4HR）或两者（PBD-3HR-LBD），并比较了它们的抗HIV-1活性和生物物理性质。我们发现肽5HR对HIV-1介导的细胞-细胞融合表现出低到中等的抑制活性，而在HR序列中添加LBD和/或PBD会导致抗HIV-1活性显著增加。含有PBD的肽，包括PBD-4HR和PBD-3HR-LBD，能够与N肽N46形成稳定的六螺旋束，并有效阻断gp41核心的形成，而含有LBD的肽，例如4HR-LBD和PBD-3HR-LBD，能够与脂质载体相互作用。这些结果表明，这些抗HIV肽中的HR序列作为一个结构域，负责其与N末端七肽重复序列中的HR序列相互作用，而PBD和LBD对于与其相应靶点的相互作用至关重要。T20、C34和T1249可能分别像4HR-LBD、PBD-4HR和PBD-3HR-LBD一样发挥作用，与不同的靶点相互作用以抑制HIV融合和进入。因此，本研究为理解肽类HIV-1融合抑制剂的作用机制以及合理设计针对HIV和其他具有I类融合蛋白的病毒的新型抗病毒肽提供了重要信息。
