Mitochondrial DNA
Mitochondrial DNA was discovered in the 1960s by Margit M. K. Nass and Sylvan Nass by electron microscopy as DNase-sensitive threads inside mitochondria, and by Ellen Haslbrunner, Hans Tuppy and Gottfried Schatz by biochemical assays on highly purified mitochondrial fractions.
Gottfried Schatz
Schatz played a leading role in elucidating the biogenesis of mitochondria and in discovering mitochondrial DNA. He recognized that this DNA encoded only a small number of mitochondrial proteins which was decisive for his further research on the import of proteins into the mitochondria and the degradation of proteins within these organelles. Schatz discovered a complex transport system that recognizes mitochondrial proteins made in the cytoplasm by specific signals attached to these proteins and then transfers them into the mitochondria. This system comprises two protein complexes, TOM and TIM, which are localized in the outer and inner mitochondrial membranes respectively. Mutations in these complexes can disrupt protein import and cause illnesses such as the neurodegenerative Mohr-Tranebjaerg syndrome, which leads to deafness. Schatz also demonstrated that the energy-requiring protease Lon regulates protein turnover within the mitochondria, thus maintaining the integrity and the proper functioning of mitochondrial DNA. Gottfried Schatz is the author of more than 200 scientific publications, three volumes of essays, an autobiography and a novel. His books have appeared in English, French, Greek and Czech translation.