D8

VACV contains approximately 25 integral or peripheral membrane proteins, of which 17 have been implicated as functioning in virus entry and/or fusion (A27, A17, H3, D8, L1, A28, H2, A21, L5, G3, G9, A16, J5, F9, I2, A26, and O3). The entry-fusion complex (EFC), an essential component of VACV-induced cell-to-cell fusion and viral core penetration, is composed of the eight core proteins A16, A21, A28, G3, G9, H2, L5, and O3. Envelope proteins A27 and H3 are involved in cell adhesion of the intracellular mature virion (MV) to the host cell glycosaminoglycan (GAG) heparan sulfate (HS). Similarly, VACV envelope protein D8, a 32-kDa type 1 membrane protein, binds to cell surface chondroitin sulfate (CS) but not to HS.