pubmed-article:7812716 | pubmed:abstractText | Viral spike proteins such as those of Semliki Forest virus (SFV) undergo a conformational change triggered by low pH which results in the fusion of the viral envelope with cellular membranes. The viral spike precursor of SFV is insensitive to low pH, and hence is fusion incompetent, until it is proteolytically cleaved to give the fusion competent mature form. | lld:pubmed |