Miniproteins against SARS-CoV-2 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is decorated with spikes, and viral entry into cells is initiated when these spikes bind to the host angiotensin-converting enzyme 2 (ACE2) receptor. Many monoclonal antibody therapies in development target the spike proteins. Cao et al. designed small, stable proteins that bind tightly to the spike and block it from binding to ACE2. The best designs bind with very high affinity and prevent SARS-CoV-2 infection of mammalian Vero E6 cells. Cryo–electron microscopy shows that the structures of the two most potent inhibitors are nearly identical to the computational models. Unlike antibodies, the miniproteins do not require expression in mammalian cells, and their small size and high stability may allow formulation for direct delivery to the nasal or respiratory system. Science, this issue p. 426 Designed miniproteins bind tightly to the SARS-CoV-2 spike protein and prevent binding to the host cell receptor. Targeting the interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptor is a promising therapeutic strategy. We designed inhibitors using two de novo design approaches. Computer-generated scaffolds were either built around an ACE2 helix that interacts with the spike receptor binding domain (RBD) or docked against the RBD to identify new binding modes, and their amino acid sequences were designed to optimize target binding, folding, and stability. Ten designs bound the RBD, with affinities ranging from 100 picomolar to 10 nanomolar, and blocked SARS-CoV-2 infection of Vero E6 cells with median inhibitory concentration (IC50) values between 24 picomolar and 35 nanomolar. The most potent, with new binding modes, are 56- and 64-residue proteins (IC50 ~ 0.16 nanograms per milliliter). Cryo–electron microscopy structures of these minibinders in complex with the SARS-CoV-2 spike ectodomain trimer with all three RBDs bound are nearly identical to the computational models. These hyperstable minibinders provide starting points for SARS-CoV-2 therapeutics.

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皮摩尔 SARS-CoV-2 微型蛋白抑制剂的从头设计

针对 SARS-CoV-2 的微蛋白 严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 带有刺突，当这些刺突与宿主血管紧张素转换酶 2 (ACE2) 受体结合时，病毒就会开始进入细胞。许多正在开发的单克隆抗体疗法都针对刺突蛋白。曹等人。设计了小的、稳定的蛋白质，它们与刺突紧密结合，并阻止其与 ACE2 结合。最好的设计以非常高的亲和力结合并防止哺乳动物 Vero E6 细胞的 SARS-CoV-2 感染。冷冻电子显微镜显示两种最有效的抑制剂的结构与计算模型几乎相同。与抗体不同，微型蛋白不需要在哺乳动物细胞中表达，并且它们的小尺寸和高稳定性可以允许制剂直接递送至鼻或呼吸系统。科学，本期第 14 页。426 设计的微型蛋白与 SARS-CoV-2 刺突蛋白紧密结合，并防止与宿主细胞受体结合。针对严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 刺突蛋白与人类血管紧张素转换酶 2 (ACE2) 受体之间的相互作用是一种有前景的治疗策略。我们使用两种从头设计方法设计抑制剂。计算机生成的支架要么围绕与刺突受体结合域 (RBD) 相互作用的 ACE2 螺旋构建，要么与 RBD 对接以识别新的结合模式，其氨基酸序列旨在优化靶点结合、折叠和稳定性。十种设计结合了 RBD，亲和力范围为 100 皮摩尔至 10 纳摩尔，并以 24 皮摩尔至 35 纳摩尔之间的中值抑制浓度 (IC50) 值阻断了 Vero E6 细胞的 SARS-CoV-2 感染。最有效的具有新的结合模式的是 56 和 64 残基蛋白质（IC50 ~ 0.16 纳克/毫升）。这些微型结合剂与 SARS-CoV-2 刺突胞外域三聚体结合的冷冻电子显微镜结构与所有三个 RBD 结合的情况几乎与计算模型相同。这些超稳定的微型结合剂为 SARS-CoV-2 疗法提供了起点。