详细记录  
题名:A study on antigenicity and receptor-binding ability of fragment 450C650 of the spike protein of SARS coronavirus
作者:Jincun Zhao, Wei Wang, Zhihong Yuan, Rujing Jia, Zhendong Zhao, Xiaojun Xu, Ping Lv, Yan Zhang, Chengyu Jiang and Xiao-Ming Gao
来源:Virology[IF=3.08], Volume 359, Issue 2, 15 March 2007, Pages 362-370
URL :http://dx.doi.org/10.1016/j.virol.2006.09.022
日期:070415
摘要: Jincun Zhaoa, Wei Wanga, Zhihong Yuana, Rujing Jiaa, Zhendong Zhaoa, Xiaojun Xua, Ping Lva, Yan Zhanga, Chengyu Jiangb and Xiao-Ming Gaoa, ,

aDepartment of Immunology, Peking University Health Science Center, Peking University, 38 Xueyuan Road, Beijing 100083, China
bInstitute of Basic Medical Sciences, Peking Union Medical College, Beijing, China

Received 5 June 2006; revised 11 July 2006; accepted 18 September 2006. Available online 20 October 2006.

Summary

The spike (S) protein of SARS coronavirus (SARS-CoV) is responsible for viral binding with ACE2 molecules. Its receptor-binding motif (S-RBM) is located between residues 424 and 494, which folds into 2 anti-parallel -sheets, 5 and 6. We have previously demonstrated that fragment 450C650 of the S protein (S450C650) is predominantly recognized by convalescent sera of SARS patients. The N-terminal 60 residues (450C510) of the S450C650 fragment covers the entire 6 strand of S-RBM. In the present study, we demonstrate that patient sera predominantly recognized 2 linear epitopes outside the 6 fragment, while the mouse antisera, induced by immunization of BALB/c mice with recombinant S450C650, mainly recognized the 6 strand-containing region. Unlike patient sera, however, the mouse antisera were unable to inhibit the infectivity of S protein-expressing (SARS-CoV-S) pseudovirus. Fusion protein between green fluorescence protein (GFP) and S450C650 (S450C650-GFP) was able to stain Vero E6 cells and deletion of the 6 fragment rendered the fusion product (S511C650-GFP) unable to do so. Similarly, recombinant S450C650, but not S511C650, was able to block the infection of Vero E6 cells by the SARS-CoV-S pseudovirus. Co-precipitation experiments confirmed that S450C650 was able to specifically bind with ACE2 molecules in lysate of Vero E6 cells. However, the ability of S450C510, either alone or in fusion with GFP, to bind with ACE2 was significantly poorer compared with S450C650. Our data suggest a possibility that, although the 6 strand alone is able to bind with ACE2 with relatively high affinity, residues outside the S-RBM could also assist the receptor binding of SARS-CoV-S protein. 23.

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