澳大新語 • 2022 UMAGAZINE 25 51 學術研究 • ACADEMIC RESEARCH 是導致SARS-CoV-2傳染性劇增的主因之一。新近 產生的Deltacron突變株由Delta突變株和Omicron 突變株雜交而成，提示我們RBD突變對新的SARSCoV-2突變株感染力的變化同樣可能起重要作用。 我們對RBD雙突變的研究結果，直接有助了解這 些「經典」和新產生的RBD新突變導致的SARSCoV-2流行，並為開發阻止SARS-CoV-2傳播的方 法提供一個理論基礎。 本研究獲澳門科技發展基金、澳門大學、澳大健康 科學學院和澳大濠江人才計劃支持。 WHO-2019-nCoV-clinical-2021-2），作為解釋 雙突變RBD導致SARS-CoV-2高度傳染性的依據。 新突變株Omicron 在南非首次出現、名為奧密克戎（Omi c ron） 的SARS-CoV-2突變株迅速在全球傳播，取 代了De l t a成為目前主要的SARS-CoV-2突變 株。Omicron突變株有18個RBD突變，其中4個 （L452R、Y478K、E484K、N501Y）與單突變和 雙突變株相同。正如從單突變RBD到雙突變RBD導 致SARS-CoV-2傳染性增加一樣，這4個RBD雙突 變與Omicron中的14個新RBD突變的組合，或許也 The COVID-19 pandemic has had a devastating impact on global public health since late 2019. As of January 2022, the SARS-CoV-2 virus, which causes a symptom of pneumonia, has infected over 318 million, and killed over 5.5 million people. SARS-CoV-2 infects human cells through the ‘receptor-binding domain’ (RBD) on its spike (S) protein to the ‘angiotensin-converting enzyme 2’ (ACE2) receptor on the human cell surface. Therefore, RBD is a key determinant of SARS-CoV-2 infection in humans. SARS-CoV-2 is rapidly evolving, with new mutations constantly generated across its genome, including the RBD. Analysis with Supercomputing Cluster in UM While most mutations did not survive evolutionary selection, some of them provide a survival advantage for the virus. This is the case for the variant strains with mutations of L452R, T478K, E484K, E484Q, and N501Y in the RBD domain, which have caused several outbreaks due to the increased infectiousness of SARS-CoV-2 with these RBD mutations. Later, several new SARS-CoV-2 strains with RBD ‘double mutations’ began to emerge. These strains contain two of the single mutations mentioned above. They are more contagious than the strains with a single 本圖顯示突變的 RBD 降低了抗體的結合力，不同顏色代表 RBD 中的抗體位結合部位：綠色是非突變RBD、淺藍色是RBD 單突變 E484、洋紅色是RBD 雙突變 L452R/T478K、黃色是 RBD 雙突變L452R/E484Q，藍色則是RBD 雙突變E484K/N501Y。 This figure shows that mutated RBD decreases an antibody’s binding capacity. The antibody sites in the RBD are highlighted in different colours. Green: Native RBD; light blue: RBD single mutant E484K; magenta: RBD double mutant L452R/T478K; yellow: RBD double mutant L452R/E484Q; blue: RBD double mutant E484K/N501Y.
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