Key galactosylated glycan receptors of SARS-CoV-2 and its inhibitor from bovine milk galactosylated glycoproteins

Illustrating the precise role of glycosylation in the interaction of spike (S) protein of SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE2) is important for understanding molecular mechanism of SARS-COV-2 infection. In this study, we utilized the antibody-overlay lectin microarrays, molecular docking analysis and glycosidase digestion to probe roles of N-glycans on S1 subunit of SARS-CoV-2 and ACE2. Our results showed that the galactosylated glycans were dominant on both S protein and ACE2. Importantly, we proved that the β1-4 galactosylated N-glycans of ACE2 were pivotal for the bindings of SARS-CoV-2 with ACE2. Furthermore, we found that the glycoproteins isolated from bovine milk contained abundant galactosylated glycans, which were similar to the glycoforms of ACE2, and could prevent the entry of SARS-CoV-2 pseudovirus. Our study provided the evidences that the β1-4 galactosylated N-glycans on ACE2 were key glycan receptors of SARS-CoV-2, and valuable strategies for developing an inexpensive protein drug to prevent SARS-CoV-2 infection.

阐明糖基化在SARS-CoV-2刺突（S）蛋白与血管紧张素转化酶2（ACE2）相互作用中的精确作用，对于理解SARS-CoV-2感染分子机制具有重要意义。在本研究中，我们运用抗体覆盖的糖基化微阵列、分子对接分析和糖苷酶消化技术，探究SARS-CoV-2和ACE2的S1亚基上N-糖苷的作用。我们的研究结果表明，半乳糖基化的糖苷在S蛋白和ACE2上均占主导地位。更重要的是，我们证实了ACE2的β1-4半乳糖基化N-糖苷对于SARS-CoV-2与ACE2的结合至关重要。此外，我们发现从牛乳中分离的糖蛋白含有丰富的半乳糖基化糖苷，其糖型与ACE2相似，并能阻止SARS-CoV-2假病毒进入。本研究提供了证据，表明ACE2上的β1-4半乳糖基化N-糖苷是SARS-CoV-2的关键糖苷受体，并为开发预防SARS-CoV-2感染的低成本蛋白药物提供了有价值的策略。