Identification of a mutation in the spike protein cleavage site in Brazilian strains of wild-type bovine coronavirus

Brazilian Journal of Microbiology

Elisabete Takiuchi²  Marco Antônio Bacellar Barreiros¹  Alice Fernandes Alfieri²  Amauri Alcindo Alfieri² 

[1] ,Universidade Estadual de Londrina Departmento de Medicina Veterinária Preventiva Laboratório de Virologia AnimalLondrina PR ,Brasil

关键词: BCoV;    sequencing;    spike protein;    cleavage site;    mutation;    BCoV;    seqüenciamento;    proteína da espícula;    sitio de clivagem;    mutação;   

DOI  :  10.1590/S1517-83822007000400021

来源: SciELO

【 摘 要 】

The spike (S) protein of coronaviruses, a type I membrane glycoprotein, is primarily responsible for entry into susceptible cells by binding with specific receptors on cells and mediating subsequent virus-cell fusion. The bovine coronavirus (BCoV) S protein is cleaved into two subunits, the N-terminal S1 and the C-terminal S2. The proteolytic cleavage site of S protein is highly conserved among BCoV strains and is located between amino acids 763 and 768 (KRRSRR). This study describes a single mutation in the S protein cleavage site of three Brazilian strains of BCoV detected in diarrheic fecal samples from calves naturally infected. The sequenced PCR products revealed that amino acid sequence of the cleavage site of our strains was KRRSSR, indicating a mutation at amino acid position 767 (R ® S). This amino acid substitution occurred due to a single nucleotide substitution in the sequence of DNA corresponding to the proteolytic cleavage site, CGT to AGT. This is the first description of this nucleotide mutation (C to A), which resulted in the substitution of arginine to serine in the S cleavage site. In this study we speculated the probable effects of this mutation in the proteolytic cleavage site using the murine hepatitis coronavirus (MHV) as a comparative model.

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