The innate immune system has an important role in developing the initial 
resistance to virus infection, and the ability of oligoadenylate synthetase to 
overcome viral evasion and enhance innate immunity is already established in 
humans. In the present study, we have tried to explore the molecular and 
structural variations present in Sahiwal (indigenous) and crossbred (Frieswal) 
cattle to identify the molecular mechanism of action of OAS1 gene in activation 
of innate immune response. The significant changes in structural alignment in 
terms of orientation of loops, shortening of β-sheets and formation of 3-10 
α-helix was noticed in Sahiwal and Frieswal cattle. Further, it has been 
observed that OAS1 from Sahiwal had better binding with APC and DTP ligand than 
Frieswal OAS1. A remarkable change was seen in orientation at the nucleoside 
base region of both the ligands, which are bound with OAS1 protein from Frieswal 
and Sahiwal cattle. The Molecular Dynamic study of apo and ligand complex 
structures was provided more insight towards the stability of OAS1 from both 
cattle. This analysis displayed that the Sahiwal cattle protein has more steady 
nature throughout the simulation and has better binding towards Frieswal in 
terms of APC and DTP binding. Thus, OAS1 protein is the potential target for 
explaining the innate immune response in Sahiwal than Frieswal.Communicated by 
Ramaswamy H. Sarma.