Updated project metadata. Imbalanced mitochondrial dNTP pools are known players in the pathogenesis of multiple human diseases. However, we have shown that dGTP is largely overrepresented over the other dNTPs in mitochondria of mouse tissues and human cultured cells. Here, we have performed affinity purification studies and identified NDUFA10, an accessory subunit of respiratory complex I, as the protein binding most of the dGTP contained in mitochondria. This interaction provides a possible link between oxidative metabolism and regulation of dNTP availability and thus with DNA maintenance.