Ribonucleoside-diphosphate reductase holoenzyme that provides the precursors necessary for viral DNA synthesis. Allows virus growth in non-dividing cells, as well as reactivation from latency in infected hosts. Catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides. The N-terminal region confers antiapoptotic activity in differentiated cells such as neurons and is important for viral reactivation to increase neural survivability. Prevents host necroptosis by targeting host RIPK1 and RIPK3, thereby hampering the formation of necroptotic RIPK1-RIPK3 complexes. May form hetero-amyloid structures with host proteins RIPK3 or ZBP1, thereby preventing RIPK3- and ZBP1-mediated necroptosis. In addition, inhibits extrinsic apoptosis by targeting host CASP8 