Provides the precursors necessary for DNA synthesis. Catalyzes the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides. [thioredoxin]-disulfide + a 2'-deoxyribonucleoside 5'-diphosphate + H2O = [thioredoxin]-dithiol + a ribonucleoside 5'-diphosphate Under complex allosteric control mediated by deoxynucleoside triphosphates and ATP binding to separate specificity and activation sites on the M1 subunit. The type of nucleotide bound at the specificity site determines substrate preference. It seems probable that ATP makes the enzyme reduce CDP and UDP, dGTP favors ADP reduction and dTTP favors GDP reduction. Stimulated by ATP and inhibited by dATP binding to the activity site (By similarity). Genetic information processing; DNA replication. Heterodimer of a large and a small subunit. Belongs to the ribonucleoside diphosphate reductase large chain family.