Less than a year after its emergence, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 22 million people worldwide with a death toll approaching 1 million. Vaccination remains the best hope to ultimately put this pandemic to an end. Here, using Trimer-Tag technology, we produced both wild-type (WT) and furin site mutant (MT) S-Trimers for COVID-19 vaccine studies. Cryo-EM structures of the WT and MT S-Trimers, determined at 3.2 Angstrom and 2.6 Angstrom respectively, revealed that both antigens adopt a tightly closed conformation and their structures are essentially identical to that of the previously solved full-length WT S protein in detergent. These results validate Trimer-Tag as a platform technology in production of metastable WT S-Trimer as a candidate for COVID-19 subunit vaccine.

中文翻译：

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S-Trimer（COVID-19的亚基疫苗候选物）的低温-EM结构

严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）出现不到一年，就已经感染了全球2200万人，死亡人数接近100万人。疫苗接种仍然是最终结束这一大流行的最大希望。在这里，使用Trimer-Tag技术，我们为COVID-19疫苗研究生产了野生型（WT）和弗林蛋白酶位点突变（MT）S-Trimers。WT和MT S-Trimers的Cryo-EM结构分别在3.2埃和2.6埃处测定，发现这两种抗原均具有紧密闭合的构象，其结构与先前解析的全长WT S蛋白的结构基本相同。洗涤剂。这些结果验证了Trimer-Tag作为生产亚稳WT S-Trimer作为COVID-19亚基疫苗候选药物的平台技术。