Int J Biol Macromol . Online ahead of print. Precise location of two novel linear epitopes on the receptor-binding domain surface of MERS-CoV spike protein recognized by two different monoclonal antibodies

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Int J Biol Macromol


. 2021 Dec 3;S0141-8130(21)02597-6.
doi: 10.1016/j.ijbiomac.2021.11.192. Online ahead of print.
Precise location of two novel linear epitopes on the receptor-binding domain surface of MERS-CoV spike protein recognized by two different monoclonal antibodies


Pan Wang ¹ , Peiyang Ding ² , Qiang Wei ³ , Aiping Wang ² , Hongliang Liu ² , Yunchao Liu ³ , Qingmei Li ³ , Yunrui Xing ³ , Ge Li ³ , Enmin Zhou ⁴ , Gaiping Zhang ⁵



Affiliations

• PMID: 34871658
• PMCID: PMC8641979
• DOI: 10.1016/j.ijbiomac.2021.11.192

Free PMC article

Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) is a coronavirus which can cause severe human respiratory diseases with a fatality rate of almost 36%. In this study, we report the generation, characterization and epitope mapping of several monoclonal antibodies against the spike receptor-binding domain (RBD) of MERS-CoV. Two monoclonal antibodies (4C7 and 6E8) that can react with linearized RBD have been selected for subsequent identification of RBD mAb-binding epitopes. Two distinct novel linear epitopes, ⁴²³FTCSQIS⁴²⁹ and ⁵⁴⁶SPLEGGGWL⁵⁵⁴,were precisely located at the outermost surface of RBD by dot-blot hybridization and ELISAs. Multiple sequence alignment analysis showed that these two peptides were highly conserved. Alanine (A)-scanning mutagenesis demonstrated that residues 423F, 428I, and 429S are the crucial residues for the linear epitope ⁴²³FTCSQIS⁴²⁹ while residues 548L, 550G, 553W, 554L for epitope ⁵⁴⁶SPLEGGGWL⁵⁵⁴. These findings may be helpful for further understanding of the function of RBD protein and the development of subsequent diagnosis and detection methods.

Keywords: MERS-CoV RBD; Monoclonal antibody; Novel linear B cell epitopes.