Structure of the catalytic domain of Mre11 fromChaetomium thermophilum

Abstract

Together with the Rad50 ATPase, the Mre11 nuclease forms an evolutionarily conserved protein complex that plays a central role in the repair of DNA double-strand breaks (DSBs). Mre11-Rad50 detects and processes DNA ends, and has functions in the tethering as well as the signalling of DSBs. The Mre11 dimer can bind one or two DNA ends or hairpins, and processes DNA endonucleolytically as well as exonucleolytically in the 3 0 -to-5 0 direction. Here, the crystal structure of the Mre11 catalytic domain dimer from Chaetomium thermophilum (CtMre11 CD ) is reported. CtMre11 CD crystals diffracted to 2.8 Å resolution and revealed previously undefined features within the dimer interface, in particular fully ordered eukaryote-specific insertion loops that considerably expand the dimer interface. Furthermore, comparison with other eukaryotic Mre11 structures reveals differences in the conformations of the dimer and the capping domain. In summary, the results reported here provide new insights into the architecture of the eukaryotic Mre11 dimer.

The MRE11–RAD50–NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair

“…MRE11 key features are an N-terminal core nuclease domain followed by a cap domain that restricts access to the nuclease active site and a flexibly linked RAD50 binding motif (21, 22, 36–39). X-ray structures of P. furiosus Mre11 revealed the two-domain architecture for the catalytic core (40).…”

“…In fact, prokaryotic Mre11 is used as a molecular avatar (an embodiment of human MRE11–essential features) for design of inhibitors against human MRE11 (47). Excitingly, high-resolution structures of eukaryotic MRN protein domains are also being solved (33, 38, 39). For eukaryotes, CtIP is also emerging as a key player in MRN functions in HR on the basis of structural analyses of the CtIP N-terminal domain (48–50).…”

“…Crystal structures of Mre11 core domain are solved for both the Mre11 alone and in complex with Rad50 from different prokaryotes and eukaryotes (21, 29, 38, 39). All crystal structures, irrespective of source, show dimer formation, yet angles for the protomer arrangement vary.…”

Structural mechanism of ATP‐dependent DNA binding and DNA end bridging by eukaryotic Rad50

“…The structure of CtMre11 RBD -Rad50 NBD reported here together with a structure of the catalytic domain dimer of CtMre11 (CtMre11 CD ) (Seifert et al, 2015) enabled us to address the architecture and dynamics of the eukaryotic Mre11-Rad50 head module by chemical cross-linking and mass spectrometry (CXMS) in combination with small-angle X-ray scattering (SAXS). We superimposed the crystal structures of CtMre11 CD and CtMre11 RBD -Rad50 NBD as rigid bodies The EMBO Journal ATP-dependent DNA binding by eukaryotic Rad50 Florian Ulrich Seifert et al onto the crystal structure of archaeal Mre11-Rad50 NBD (PDB code 3AVO), resulting in a very reasonable fit between the Mre11 dimer and the Rad50 dimer ( Fig 3A).…”

“…NBD reported here together with a structure of the catalytic domain dimer of CtMre11 (CtMre11 CD ) (Seifert et al, 2015) enabled us to address the architecture and dynamics of the eukaryotic Mre11-Rad50 head module by chemical cross-linking and mass spectrometry (CXMS) in combination with small-angle X-ray scattering (SAXS Fig S3) (Tosi et al, 2013;Leitner et al, 2014). Cross-links were found between all three different polypeptide chains (Fig 3B) , map with a lysine C a -lysine C a distance of 15-41 Å , validating the docked model ( Fig 3C).…”