Adjacent mutations in the archaeal Rad50 ABC ATPase D-loop disrupt allosteric regulation of ATP hydrolysis through different mechanisms

Zachary K. Boswell, Marella D. Canny, Tanner A. Buschmann, Julie Sang, Michael P. Latham

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


DNA damage is the driving force for mutation and genomic instability, which can both lead to cell death or carcinogenesis. DNA double strand breaks are detected and processed in part by the Mre11-Rad50-Nbs1 protein complex. Although the Mre11-Rad50-Nbs1 complex is essential, several spontaneous mutations have been noted in various cancers. One of these mutations, within a conserved motif of Rad50, resulted in an outlier curative response in a clinical trial. We show through biochemical and biophysical characterization that this cancer-associated mutation and a second mutation to the adjacent residue, previously described in a breast cancer patient, both have gain-of-function Rad50 ATP hydrolysis activity that results not from faster association of the ATP-bound form but faster dissociation leading to less stable Rad50 dimer. This disruption impairs the regulatory functions of the protein complex leading to a loss of exonuclease activity from Mre11. Interestingly, these two mutations affect Rad50 structure and dynamics quite differently. These studies describe the relationship between function, structure, and molecular motions in improperly regulated Rad50, which reveal the underlying biophysical mechanism for how these two cancer-associated mutations affect the cell.

Original languageEnglish (US)
Pages (from-to)2457-2472
Number of pages16
JournalNucleic acids research
Issue number5
StatePublished - Mar 18 2020
Externally publishedYes

Bibliographical note

Funding Information:
Welch Foundation [D-1876 to M.P.L.]; Cancer Prevention and Research Institute of Texas [RP180553 to M.P.L.]; Welch Summer Scholars Program [to J.S.]. Funding for open access charge: Cancer Prevention and Research Institute of Texas.

Publisher Copyright:
© 2019 The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.


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