Abstract 1291 Complicated relationship of the DNA Polymerases Gamma and Beta

Mitochondria are cellular organelles that supply energy for the entire human body and its function.Their function is not only crucial for our daily lives but also depends on the maintenance of their semi-autonomous genome.Defects of the mitochondrial genome result in the development of human mitochondrial diseases, which range from debilitating myopathies to devastating early-onset multisystemic syndromes with short life expectancy (e.g., Alpers syndrome).Defects in mitochondrial DNA (mtDNA) maintenance have also been linked to other prominent and world-wide disorders such as Parkinson's and Alzheimer's, autism spectrum disorders, diabetes, various cancer types, and aging.These diseases affect not only a person's daily life but can lead to either a rapid or slow decline of health.Notably, there is currently no cure available for any of the mtDNA associated diseases.The major cause of mtDNA maintenance defects are malfunctions of the mtDNA replication machinery (replisome).Twinkle helicase is the key component of the mitochondrial replisome and several mutations to its residues have been associated with the pathogenesis of human disorders.The role of the N-terminal domain (NTD) of Twinkle is elusive and molecular basis of conditions developing upon mutations to its residues are not clear.Here we sought to characterize the biochemical and kinetic implication of selected pathogenic mutations in NTD (G92S, K184E, and R192C), employing biolayer interferometry and classical biochemical approaches.Our results hint on the biochemical consequences of the mutations and provide a novel approach to study concerted action of the mitochondrial replisome components.