Rad50 is a 150 kDa member of the Rad50 subfamily, SMC (structural maintenance of chromosomes) family of DNA-associated genes. It is ubiquitously expressed, and associates with MRE11 and NBS1 to form an MRN complex. This complex stabilizes ATM kinase, thus contributing to DNA repair, and also participates in the suppression of DNA rereplication in dividing cells.
Human Rad50 is 1312 amino acids (aa) in length. It has an apparent ATP binding site (aa 36 - 43) plus a coiled-coil region (aa 228 - 598) followed by a 'zinc-hook' domain (aa 635 - 734) that mediates homodimerization. There are multiple Rad50 splice variants. An alternate start site exists at Met140, there is a single Lys substitution for aa 723 - 1312, and three Lys substitute for aa 555 - 1312. Over aa 518 - 881, human Rad50 is 96% aa identical to mouse Rad50.