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

Abstract

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.

Isolation in HRT-18 cells and molecular analysis of a BCoV strain from diarrheic feces of naturally infected calves

“…Despite the small size of the N gene fragment analyzed, the identity among Brazilian BCoV strains and the other BCoV strains used in this study were lower (97.6 to 98.5%) than the identity among other published sequences (98.1 to 100%) (data not shown). Since the region of the N gene amplified by the semi-nested PCR was highly conserved among coronaviruses, it is possible that other genes also present low identity; this has previously been observed in the S gene from other Brazilian BCoV strains (Takiuchi et al, 2007;2008). Thus, additional studies are necessary for molecular characterization of Brazilian BCoV strains.…”

Global Trends of Emerging Infectious Diseases and the Impacts on Biodiversity: Spillover, Diversity and the Role of Bats in Evolutionary Relationships as Zoonotic Virus Reservoirs

“…The spike (S) protein, a type I membrane glycoprotein, is primarily responsible for the entry of the virus into susceptible cells through initial interaction with specific cell receptors and subsequent mediation of the fusion between the virus-cell membranes and consequently the entry of the virus in the cytoplasm [55] (Fig. 2)…”

Starting Anti-COVID-19 Drug Discovery with Natural Products

“…Another characteristic of the S1 subunit is that it has regions in its sequence that have great variability, regions that are called: hypervariable region 1 (HVR I), delimited by amino acid residues 38 to 69; hypervariable region 2 (HVR II), delimited by amino acid residues 91 to 141; and the hypervariable region 3 (HVR III) comprising amino acid residue 250 to 387. Several studies have demonstrated the importance of these three hypervariable regions in the direct interaction with neutralizing antibodies and, therefore, constitute the serotype-specific determinants presented by the different strains of coronavirus (Takiuchi et al 2007;Jaimes et al 2020).…”