Involved in DNA double-strand break repair (DSBR). The RAD50/MRE11 complex possesses single-strand endonuclease activity and ATP-dependent double-strand-specific exonuclease activity. RAD50 provides ATP-dependent control of MRE11 by unwinding and/or repositioning DNA ends into the MRE11 active site (By similarity). Binds 1 zinc ion per homodimer. Homodimer. Forms a complex with MRE11. Expressed in late sporogonial stages. The zinc-hook, which separates the large intramolecular coiled coil regions, contains 2 Cys residues that coordinate one molecule of zinc with the help of the 2 Cys residues of the zinc-hook of another RAD50 molecule, thereby forming a V-shaped homodimer. Belongs to the SMC family. RAD50 subfamily.