Glutaredoxin necessary for virion morphogenesis and virus replication. Functions as a thiol-disulfide transfer protein between membrane-associated A2.5 and substrates L1 or F9. The complete pathway for formation of disulfide bonds in intracellular virion membrane proteins sequentially involves oxidation of E10, A2.5 and G4. Exhibit thioltransferase and dehydroascorbate reductase activities in vitro (By similarity). Homodimer (By similarity). Interacts with A2.5; this interaction involves formation of a transient disulfide-bonded intermediate, allowing disulfide bond transfer. Interacts with L1; this interaction involves formation of a transient disulfide-bonded intermediate, allowing disulfide bond transfer (By similarity). Belongs to the glutaredoxin family.