Fusion glycoprotein F0 of the human respiratory syncytial virus (RSV) is a critical fusion glycoprotein that facilitates entry of the virus into host cells by mediating the fusion of the viral and cellular membranes. This class I fusion protein is synthesized as an inactive precursor (F0), which undergoes cleavage to form two disulfide linked subunits, F1 and F2, that are essential for its fusion activity. The RSV F protein exists in two conformations: a metastable prefusion form and a stable postfusion form, with the prefusion form being a major target for neutralizing antibodies due to its role in viral entry. The structural transitions of the F protein during the fusion process are crucial for its function, making it a significant focus in the development of vaccines and antiviral therapies against RSV infections.