Monkeypox virus (MPXV) is double-stranded DNA virus belonging to the genus orthopoxvirus that causes a smallpox-like disease in humans. M1R is homologous to the vaccinia virus L1 protein, a transmembrane protein found on the surface of mature IMV particles. And M1R is the component of the entry fusion complex (EFC), which consists of 11 proteins. During cell infection, this complex mediates entry of the virion core into the host cytoplasm by a two-step mechanism consisting of lipid mixing of the viral and cellular membranes and subsequent pore formation.