Virucidal activity of a scorpion venom peptide variant mucroporin-M1 against measles, SARS-CoV and influenza H5N1 viruses

► We investigated the antiviral activities of mucroporin and optimized mucroporin-M1. ► Mucroporin and mucroporin-M1 were scorpion venom-derived host defense peptides. ► Mucroporin-M1 but not mucroporin had antiviral activities against tested viruses. ► The tested viruses were measles, SARS-CoV and influenza H5N1 viruses. ► Mucroporin-M1 exerted its effects on viruses by directly binding to virus membranes.