Structure, dynamics, and function of the viroporins Vpu from HIV and p7 from HCV

描述（由申请人提供）：感染人类免疫缺陷病毒（HIV）和丙型肝炎病毒（HCV）是人类发病和死亡的最重要原因之一。在世界范围内，有超过4000万人（艾滋病毒）和1.7亿人（丙型肝炎病毒）感染了这些病毒。在美国，0.6% （HIV）和1.7% （HCV）的人口被感染。超过25%的艾滋病毒感染者同时感染了丙型肝炎病毒（高达90%的静脉注射吸毒者）。尽管高度活跃的抗逆转录病毒疗法取得了成功，但迫切需要开发针对新受体的全新类别的抗艾滋病毒药物，以确保对耐药性发展的不同敏感性。目前丙型肝炎的治疗方法严重不足，需要多种第一代抗丙型肝炎药物。HIV-1和HCV都有病毒孔蛋白，这是一种具有离子通道活性的小膜蛋白，也是潜在的药物靶点。拟议的研究建立在最近的结果之上，并代表了我们对膜蛋白结构研究的实质性扩展。确定来自HIV-1的Vpu（病毒蛋白“u”）和来自HCV的p7蛋白的结构对于了解其生物活性的分子机制和发现干扰这些活性的药物至关重要。我们的核磁共振方法特别适合于确定这些蛋白质在磷脂双层的天然环境中的结构。由于我们的方法不受多肽分子质量的影响，因此同位素标记的Vpu与未标记的细胞伴侣结合的研究并不比单独研究Vpu更难。我们将通过核磁共振探索SAR（结构活性关系）对Vpu和p7的应用，作为膜结合受体的例子，并确定药物的潜在结合位点。公共卫生相关性：人类免疫缺陷病毒（HIV）和丙型肝炎病毒（HCV）感染是人类发病和死亡的最重要原因之一。在世界范围内，有超过4000万人（艾滋病毒）和1.7亿人（丙型肝炎病毒）感染了这些病毒。在美国，0.6% （HIV）和1.7% （HCV）的人口被感染。超过25%的艾滋病毒感染者同时感染了丙型肝炎病毒（高达90%的静脉注射吸毒者）。HIV是逆转录病毒科的一种慢病毒。它通过感染CD4+ T和其他免疫系统细胞引起获得性免疫缺陷综合征（AIDS）；由此导致的免疫功能下降意味着机会性感染，如结核病和卡波西肉瘤，以及合并感染，如丙型肝炎病毒，对人类健康产生毁灭性影响。高效抗逆转录病毒疗法（HAART）对许多患者有效；然而，艾滋病毒的遗传变异性意味着需要针对其他分子靶点的药物来对抗在治疗病原体基因组整合到宿主DNA中的疾病过程中不可避免地产生的耐药性。拟议的研究将提供Vpu的结构信息，Vpu是病毒生命周期中的一种关键蛋白质，有可能成为开发治疗艾滋病药物的新靶点。HCV是黄病毒科包膜单链RNA病毒的一员，主要感染肝细胞。大多数丙型肝炎病毒感染是持续的，并导致肝脏疾病，包括肝炎、肝硬化和肝细胞癌。因此，HCV是全国肝移植的主要指标。目前丙型肝炎病毒感染的治疗包括给药聚乙二醇干扰素和利比韦林，有许多局限性；它不仅耗时、昂贵、耐受性差，而且只对一小部分病例有效。开发有效的抗丙型肝炎病毒药物是当务之急，特别是因为治疗艾滋病毒和丙型肝炎病毒合并感染患者遇到的困难。拟议的研究将提供关于p7的结构信息，p7是病毒生命周期中的关键蛋白，有可能成为开发治疗丙型肝炎药物的新靶点。

DESCRIPTION (provided by applicant): Infections with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are among the most significant causes of human morbidity and mortality. Worldwide, there are more than 40 million (HIV) and 170 million (HCV) people infected with these viruses. In the United States, 0.6% (HIV) and 1.7% (HCV) of the population is infected. More than 25% of those infected with HIV are co-infected with HCV (up to 90% of i.v. drug users). Despite the success of highly active anti-retroviral therapy, there is an urgent need to develop entirely new classes of anti-HIV drugs targeted to novel receptors in order to ensure different susceptibilities to the development of resistance. Current therapies for HCV are grossly inadequate, and multiple first-generation anti- HCV drugs are needed. Both HIV-1 and HCV have a viroporin, a small membrane protein with ion channel activity and a potential drug target. The proposed research builds upon recent results, and represents a substantial expansion of our structural studies of membrane proteins. Determining the structures of Vpu (Virus protein "u") from HIV-1 and the p7 protein from HCV are essential in order to understand the molecular mechanisms of their biological activities and to nucleate the discovery of drugs that interfere with these activities. Our NMR methods are particularly well suited for determining the structures of these proteins in their native environment of phospholipid bilayers. And since our approach is unaffected by the molecular mass of the polypeptides, studies of isotopically labeled Vpu bound to unlabeled cellular partners are no more difficult than for Vpu alone. We will explore the application of SAR (structure activity relationships) by NMR to Vpu and p7 as examples of membrane-bound receptors and to identify potential binding sites for drugs. PUBLIC HEALTH RELEVANCE: Infections with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are among the most significant causes of human morbidity and mortality. Worldwide, there are more than 40 million (HIV) and 170 million (HCV) people infected with these viruses. In the United States, 0.6% (HIV) and 1.7% (HCV) of the population is infected. More than 25% of those infected with HIV are co-infected with HCV (up to 90% of i.v. drug users). HIV is a lentivirus in the Retroviridae family. It causes the acquired immunodeficiency syndrome (AIDS) by infecting CD4+ T and other cells of the immune system; the resulting decline of immune functions means that opportunistic infections, such as tuberculosis and Kaposi's sarcoma, and co-infections, such as HCV, have devastating effects on human health. HAART (highly active antiretroviral therapy) is effective in many patients; however, the genetic variability of HIV means that drugs against additional molecular targets are needed to combat resistance that inevitably develops in the course of treating a disease in which the genome of the causative agent is integrated into the host DNA. The proposed studies will provide structural information about Vpu, a key protein in the viral lifecycle that has the potential to be a new target for the development of drugs to treat AIDS. HCV is a member of the Flaviviridae family of enveloped single-stranded RNA viruses that mainly infects hepatocyte. Most HCV infections are persistent and lead to liver diseases, including hepatitis, cirrhosis, and hepatocellular carcinoma. Consequently, HCV is the leading indicator for liver transplantation in the Nation. Current therapy for HCV infections consists of the administration of pegylated interferon and ribivirin and has many limitations; not only is it lengthy, expensive and poorly tolerated, but also it works in only a fraction of cases. The development of effective anti-HCV drugs is a high priority, especially because of the difficulties encountered in treating patients co-infected with HIV and HCV. The proposed studies will provide structural information about p7, a key protein in the viral lifecycle that has the potential to be a new target for the development of drugs to treat hepatitis C.