The cysteines in position 1 and 86 of rat interferon‐α₁ are indispensable for antiviral activity

Abstract

The human, bovine, murine and rat interferon (IFN)-~t families contain 4 conserved cysteines located at positions 1, 29, 99 and 139 that are involved in disulfide bridges. Rat and murine IFN-~t subspecies carry a fifth Cys (Cys-86) which is not conserved in bovine and human IFN-ct subspecies except for human IFN-cfi. Changing Cys-86 in rat IFN-cq into Ser or Tyr virtually abolished antiviral activity. As shown by others, the substitution of Cys-86 to Ser in human IFN-cq had no pronounced effect on activity. This suggests that in contrast to human and bovine IFN-~t, Cys-86 in rodent IFN-ct plays a crucial role in receptor binding. Changing Cys-I to Gly in rat IFN-cq also destroyed activity, in agreement with results obtained in the human IFN-cq system.

Molecular characterization and expression analysis of two type I interferons from Asian Seabass ( Lates calcarifer ) during nervous necrosis virus infection

“…Alignment of IFN protein sequences reveals that almost all teleosts have at least 2 conserved cysteine residues, one immediately after the signal peptide sequence and the other approximately after 80% through IFN sequence (Milne et al, 2018). Many studies suggest that the presence of cysteine residues is essential for proper protein conformation and biological activity, and the removal of this disulphide bridge (substitution of Cys29 by serine in Cys29‐Cys139 disulfide bridge) may result in a reduction in its antiviral and anti‐proliferative activity (Beilharz et al, 1986; Spanjaard et al, 1989).…”