– Prevents cell to cell fusion by interacting with and directing the viral K2 protein on the host plasma membrane. The A56-K2 complex associates with components of the entry fusion complex (EFC) presumably to avoid superinfection and syncytium formation. Via its interaction with C3/VCP protein, protects the infected cell and probably also the extracellular enveloped virus from complement attack. Vaccinia virus (strain Copenhagen) OPG185 Protein (His) is expressed in E. coli expression system with N-6xHis tag. The predicted molecular weight is 31.6 kDa and the accession number is P20978.