Ribonucleoside-diphosphate reductase holoenzyme provides the precursors necessary for viral DNA synthesis. Allows virus growth in non-dividing cells. Catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides (By similarity). [thioredoxin]-disulfide + a 2'-deoxyribonucleoside 5'-diphosphate + H2O = [thioredoxin]-dithiol + a ribonucleoside 5'-diphosphate Maximal ribonucleotide reductase activity requires the presence of Mg(2+) ions. Under complex allosteric control mediated by deoxynucleoside triphosphates and ATP binding. The type of nucleotide bound at the specificity site determines substrate preference. It seems probable that ATP makes the enzyme reduce CDP and UDP, whereas dGTP favors ADP reduction and dTTP favors GDP reduction (By similarity). Optimum pH is 8.0 and above. Genetic information processing; DNA replication. Heterotetramer composed of a homodimer of the large subunit (R1) and a homodimer of the small subunit (R2). Larger multisubunit protein complex are also active, composed of (R1)n(R2)n (By similarity). Expressed early in the viral replicative cycle. Belongs to the ribonucleoside diphosphate reductase large chain family.