Identification of minimal motif of linear B cell epitope on the cytoplasmic domain of porcine epidemic diarrhea virus S protein

Abstract:

[Background] S protein is the main structural and immunogenic protein of PEDV. In our previous work, two linear B cell epitopes (BCE) containing short peptides were identified in the cytoplasmic domain of S protein. [Objective] To identify the minimal motif of the linear BCE were identified in the cytoplasmic domain of PEDV S protein. [Methods] Serial 8-mers, advancing one aa once on the short peptide, were prokaryotically expressed. Positive 8-mers were identified by Western Blot using rabbit anti-S serum as the primary antibody and the minimal motif of the linear BCE was identified within the cytoplasmic domain of S protein. [Results] The two short peptides within the cytoplasmic domain of S protein contained the same epitope, and the minimum motif of the epitope was ¹³⁷¹QPYE¹³⁷⁴. Homologous analysis showed that the BCE motif was conserved. [Conclusion] The minimum motif of the BCE within the cytoplasmic domain of S protein was determined as ¹³⁷¹QPYE¹³⁷⁴. Identification of antigen epitope on S protein helps to improve the understanding of its structure and function.

Key words:porcine epidemic diarrhea virus;S protein;cytoplasmic domain;linear B cell epitope;minimal motif identification