Wong Swee Kee, Li Wenhui, Moore Michael J, Choe Hyeryun, Farzan Michael
Partners AIDS Research Center, Brigham and Women's Hospital, Department of Medicine (Microbiology and Molecular Genetics), Harvard Medical School, Boston, Massachusetts 02115, USA.
J Biol Chem. 2004 Jan 30;279(5):3197-201. doi: 10.1074/jbc.C300520200. Epub 2003 Dec 11.
The coronavirus spike (S) protein mediates infection of receptor-expressing host cells and is a critical target for antiviral neutralizing antibodies. Angiotensin-converting enzyme 2 (ACE2) is a functional receptor for the coronavirus (severe acute respiratory syndrome (SARS)-CoV) that causes SARS. Here we demonstrate that a 193-amino acid fragment of the S protein (residues 318-510) bound ACE2 more efficiently than did the full S1 domain (residues 12-672). Smaller S protein fragments, expressing residues 327-510 or 318-490, did not detectably bind ACE2. A point mutation at aspartic acid 454 abolished association of the full S1 domain and of the 193-residue fragment with ACE2. The 193-residue fragment blocked S protein-mediated infection with an IC(50) of less than 10 nm, whereas the IC(50) of the S1 domain was approximately 50 nm. These data identify an independently folded receptor-binding domain of the SARS-CoV S protein.
冠状病毒刺突（S）蛋白介导表达受体的宿主细胞感染，是抗病毒中和抗体的关键靶点。血管紧张素转换酶2（ACE2）是导致严重急性呼吸综合征（SARS）的冠状病毒（SARS-CoV）的功能性受体。在此，我们证明S蛋白的一个193个氨基酸的片段（第318至510位氨基酸残基）比完整的S1结构域（第12至672位氨基酸残基）更有效地结合ACE2。表达第327至510位或第318至490位氨基酸残基的较小S蛋白片段未检测到与ACE2的结合。天冬氨酸454处的点突变消除了完整S1结构域和193个氨基酸残基片段与ACE2的结合。193个氨基酸残基的片段以小于10 nM的半数抑制浓度（IC50）阻断S蛋白介导的感染，而S1结构域的IC50约为50 nM。这些数据确定了SARS-CoV S蛋白的一个独立折叠的受体结合结构域。
