시간에 따른 Methanocaldococcus jannaschii Mre11-Rad50 복합체의 구조 변화 연구

Abstract

Genomic integrity of cells is threatened by environmental agents and cellular metabolism such as failures in DNA replication. DNA double-strand breaks (DSBs) are one of the most dangerous form of DNA damage. Therefore, the repair of double- strand breaks in DNA is an essential process in all organisms. The Mre11-Rad50 complex is an evolutionarily conserved complex of two Rad50 ATPase and a dimer of the Mre11 nuclease that important factor of biological response to DSBs. MR complex senses DSBs, processes broken DNA ends and triggers signaling pathway. Rad50 is a member of the ATP Binding Cassette (ABC) protein superfamily, ATP binding promotes dimerization that likely connected ATP hydrolysis to dimer dissociation and DNA binding. It is thought that the energy of ATP hydrolysis is used to conformational changes, which is functionally important. Therefore, I focused on the effect of ATP hydrolysis to MR complex. To demonstrate what ATP hydrolysis effect on MR complex and how this interaction related with the DNA-binding of MR complex. I can observed initial stage of ATP hydrolysis by time-resolved ATP-hydrolysis protein crystal of MjMR complex. Compared with known structure, it gives an insight of beginning of changes. Here, my results show a trigger residues of conformational change that approximately important to biological function. In addition, affinity of DNA-binding according to the Rad50 mutations. Through these experimental data, suggesting that which region of Rad50 is critical for conformational change and interaction with DNA that how Rad50 affects the Mre11 nuclease activity.