近期高度传播的SARS-CoV-2变异体的出现,说明了更好地理解病毒与其宿主细胞结合的分子细节以及开发抗病毒策略的紧迫性。虽然许多研究集中于血管紧张素转换酶2受体在感染中的作用,但其他研究表明细胞附着因子如糖基的重要作用。在这里,我们使用原子力显微镜研究这些早期结合事件,重点关注唾液酸(SA)的作用。我们展示了SARS-CoV-2与9-
CBMs (carbohydrate-binding modules) are a class of polypeptides usually associated with carbohydrate-active enzymatic sites. We have characterized a new member of the CBM40 family, coded from a section of the gene NanI from Clostridium perfringens. Glycan arrays revealed its preference towards α(2,3)-linked sialosides, which was confirmed and quantified by calorimetric studies. The CBM40 binds to α(2,3)-sialyl-lactose with a Kd of ∼30 μM, the highest affinity value for this class of proteins. Inspired by lectins' structure and their arrangement as multimeric proteins, we have engineered a dimeric form of the CBM, and using SPR (surface plasmon resonance) we have observed 6–11-fold binding increases due to the avidity affect. The structures of the CBM, resolved by X-ray crystallography, in complex with α(2,3)- or α(2,6)-sialyl-lactose explain its binding specificity and unusually strong binding.