UC Riverside

This study enhances our understanding of mitochondrial transcription factor A (TFAM) and its pivotal roles in maintaining mitochondrial DNA (mtDNA) integrity through a series of investigations. First, we focused on Glutamic acid 187 (E187) in the β-elimination reaction, which is an essential step in mtDNA repair. Using kinetic analyses and comprehensive computer simulations, we demonstrated how E187 accelerates the reaction rates quantitatively, providing critical insights into the molecular mechanisms that facilitate DNA repair within mitochondria.Next, our study has demonstrated the intrinsic 5’dRp lyase activity of TFAM, observed through in vitro experiments. The activity rate is comparable with that of polymerase β, implying TFAM's vital role in the mitochondrial Base Excision Repair (BER) pathway. Such functionality is particularly significant since it indicates TFAM can reduce the accumulation of toxic DNA repair intermediates. These intermediates if unrepaired, could lead to mitochondrial dysfunction, thus highlighting the broader implications of TFAM in maintaining cellular health and preventing disease progression. Finally, we are working on developing an innovative mass spectrometry method to detect TFAM-DNA-protein complexes (DPCs) in cells. This novel method aims to provide structural insights into the ways TFAM interacts with damaged mtDNA and allow us to detect other protein candidates that are binding with AP-mtDNA under physiological condition. The development of this technique is an important step towards understanding the complex dynamics of mtDNA-protein interactions within mitochondria. Taken together, the above projects help with our understanding of TFAM's molecular interactions and regulatory roles and broaden our knowledge of mtDNA stability. By elucidating the mechanisms that protect mtDNA integrity, our research contributes to the broader scientific understanding of mitochondrial function and its impact on cellular health.