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Free keywords:
ELECTRON-MICROSCOPY, END-RESECTION, CRYOELECTRON MICROSCOPY,
THERMOPHILIC ARCHAEA, CRYSTAL-STRUCTURE, NUCLEASE COMPLEX, CHI
RECOGNITION, RECBCD ENZYME, CRYO-EM, HELICASEBiochemistry & Molecular Biology; Biophysics; DNA double-strand break repair, Cryo-electron microscopy, Nuclease, DNA
resection, FtsK/HerA ATPase;
Abstract:
DNA double-strand breaks can be repaired by homologous recombination,
during which the DNA ends are long-range resected by helicase-nuclease
systems to generate 30 single strand tails. In archaea, this requires
the Mre11-Rad50 complex and the ATP-dependent helicase-nuclease complex
HerA-NurA. We report the cryo-EM structure of Sulfolobus solfataricus
HerA-NurA at 7.4 angstrom resolution and present the pseudo-atomic model
of the complex. HerA forms an ASCE hexamer that tightly interacts with a
NurA dimer, with each NurA protomer binding three adjacent HerA HAS
domains. Entry to NurA's nuclease active sites requires dsDNA to pass
through a 23 angstrom wide channel in the HerA hexamer. The structure
suggests that HerA is a dsDNA translocase that feeds DNA into the NurA
nuclease sites. (C) 2014 Federation of European Biochemical Societies.
Published by Elsevier B.V. All rights reserved.
