ABSTRACT
Corona virus disease 2019 is an acute infectious disease caused by SARS-CoV-2 infection and has entered the state of global pandemic. Spike protein ( S protein) , a key protein that mediates SARS-CoV-2 to infect host cells, has the characteristics of specific receptor binding and membrane fusion, playing an important role in host tropism and virulence. The spontaneous closed and open conformation of S protein trimer is crucial for receptor binding and initiation of conformational changes in membrane fusion, and its unique furin recognition site may be a crucial factor leading to high infectivity. Therefore, to study the structure and function of SARS-CoV-2 S protein and its receptor has important implications for invasion mechanisms of SARS- CoV-2 and the development of relevant targeted drugs.