design and rapid production of a drug-screening target from the highly conserved HR1 region of the viral spike protein (S2)

SARS-CoV-2是一种新型冠状病毒，是当前全球大流行的病原体，已导致200多万人感染，12.5万人死亡，并造成严重的经济影响。目前还没有可用的预防、治疗或疫苗，护理只是支持性的。此外，21世纪出现了多种致命的人类冠状病毒(SARS-CoV、MERS-CoV，以及现在的SARS-CoV-2)。迫切需要新的选择来抗击这一流行病和未来不可避免的流行病。 冠状病毒通过一种保守的进入细胞的机制感染细胞，该机制由多个家族的包膜病毒共享，其中三聚体病毒刺突蛋白的两个区域(HR1和HR2)形成一个高度稳定的6-螺旋束结构，并列在病毒和细胞膜上，诱导膜融合。抑制这种6-螺旋束的形成可以阻止病毒进入并防止感染。我们的实验室专门从事与结构导向设计相结合的创新对映体筛选技术(镜像噬菌体展示)，以生产新型、合成的D-肽病毒进入抑制剂，包括CPT31，我们的高效、广谱活性的HIV-1 D-肽抑制剂已被FDA批准用于临床研究。我们和其他人对SARS的研究表明，这些抑制策略应该能成功地阻止当前的冠状病毒。SARS是一种高度相关的冠状病毒，在尖峰HR1与SARS-CoV-2有86%的同源性(和95%的相似性)。D-肽(由镜像D-氨基酸组成的肽)在体内不能被蛋白酶消化，因此具有显著的治疗优势，包括延长半衰期、降低剂量、降低免疫原性(不被MHC消化)，以及在富含蛋白酶的环境中(如呼吸道)的耐用性。 在这项为期一年的拨款申请中，我们将首先设计和合成SARS-CoV-2基于HR1的三聚体多肽。这些多肽准确地模拟了进入病毒时出现在病毒上的HR1，因此是宝贵的药物筛选靶点。然后，我们将在镜像噬菌体展示中使用这些模拟物作为靶标，以确定阻止SARS-CoV-2和未来SARS相关冠状病毒的D-肽抑制剂。

SARS-CoV-2, a novel coronavirus, is the causative agent of the current worldwide pandemic that has already led to over 2 million infections, 125,000 deaths, and severe economic impact. Currently no preventatives, treatments, or vaccines are available, and care is solely supportive. Additionally, the 21st century has seen the emergence of multiple lethal human coronaviruses (SARS-CoV, MERS-CoV, and now SARS- CoV-2). There is an urgent need for new options to combat this and inevitable future pandemics. Coronaviruses infect cells using a conserved entry mechanism shared by enveloped viruses across multiple families in which two regions of the trimeric viral spike protein (HR1 and HR2) form a highly stable 6- helix bundle structure, juxtaposing the viral and cellular membranes to induce membrane fusion. Inhibiting formation of this 6-helix bundle stops viral entry and prevents infection. Our lab specializes in an innovative enantiomeric screening technology (mirror-image phage display) in concert with structure-guided design, to produce novel, synthetic, D-peptide viral entry inhibitors, including CPT31, our highly potent, broadly active HIV-1 D-peptide inhibitor that has been cleared by the FDA for clinical studies. Research by us and others on SARS, a highly related coronavirus that shares 86% identity (and 95% similarity) to SARS-CoV-2 in the spike HR1, indicate that these inhibition strategies should successfully block the current coronavirus. D-peptides (peptides composed of mirror-image D-amino acids) cannot be digested by proteases in the body and, therefore, possess significant therapeutic advantages including extended half-life, lower dosing, reduced immunogenicity (not digested for MHC presentation), and durability in protease-rich environments such as the respiratory tract. In this one-year grant application, we will first design and synthesize SARS-CoV-2 trimeric HR1-based peptides. These peptides accurately mimic HR1 as it appears on the virus during entry and are therefore invaluable drug screening targets. We will then use these mimics as targets in mirror-image phage display to identify D-peptide inhibitors of SARS-CoV-2 that block it and future SARS-related coronaviruses.