Due to the complex nature of biomolecules,computational studies of inter-action in proteins are primarily based on classical force fields.However,the inherent limitations of the classical force fields significantly reduced the accuracy and reliability of computational predictions of protein structure and dynamics,protein-ligand bind-ing,protein-protein interaction,etc.In order to significantly improve the accuracy of computational predictions of biomolecular interactions in a fundamental way,it is important to develop practical computational approaches that describe biomolecular interactions based on fundamental theory of quantum mechanics.In this talk,we will discuss our recent effort to develop quantum fragment based computational methods to study protein structure and interaction dynamics,with an emphasis on ab initio molecular dynamics(AIMD)approach to studying protein structure and interaction dynamics.