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. Binds 1 zinc ion per homodimer. Homodimer (By similarity). Forms a complex with MRE11. 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. Present with 830 molecules/cell in log phase SD medium. Belongs to the SMC family. RAD50 subfamily.