title: Human RAD50 makes a functional DNA-binding complex.
abstract: The MRE11-RAD50-NBS1 (MRN) complex has several distinct functions in DNA repair including important roles in both non-homologous end-joining (NHEJ) and homologous recombination (HR). The biochemical activities of MR(N) have been well characterized implying specific functional roles for the components. The arrangement of proteins in the complex implies interdependence of their biochemical activities making it difficult to separate specific functions. We obtained purified human RAD50 and observed that it binds ATP, undergoes ATP-dependent conformational changes as well as having ATPase activity. Scanning force microscopy analysis clearly showed that RAD50 binds DNA although not as oligomers. RAD50 alone was not functional in tethering DNA molecules. ATP increased formation of RAD50 multimers which were however globular lacking extended coiled coils, in contrast to the MR complex where ATP induced oligomers have obvious coiled coils protruding from a central domain. These results suggest that MRE11 is important in maintaining the structural arrangement of RAD50 in the protein complex and perhaps has a role in reinforcing proper alignment of the coiled coils in the ATP-bound state.
authors.affiliation: Department of Genetics, Cancer Genomics Center, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Eri
authors.initials: E
authors.lastname: Kinoshita
authors.affiliation: Department of Genetics, Cancer Genomics Center, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Sari
authors.initials: S
authors.lastname: van Rossum-Fikkert
authors.affiliation: Department of Genetics, Cancer Genomics Center, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Humberto
authors.initials: H
authors.lastname: Sanchez
authors.affiliation: Department of Genetics, Cancer Genomics Center, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Aryandi
authors.initials: A
authors.lastname: Kertokalio
authors.affiliation: Department of Genetics, Cancer Genomics Center, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands; Department of Radiation Oncology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands. Electronic address: c.wyman@erasmusmc.nl.
authors.forename: Claire
authors.initials: C
authors.lastname: Wyman
mesh_terms: D017766:Acid Anhydride Hydrolases; D000255:Adenosine Triphosphate / Q000737:chemistry; D018797:Cell Cycle Proteins / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D045643:DNA Repair Enzymes / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D006801:Humans; D000076228:MRE11 Homologue Protein; D046912:Multiprotein Complexes / Q000737:chemistry*; D009687:Nuclear Proteins / Q000737:chemistry*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; D046912:Multiprotein Complexes; C112156:NBN protein, human; D009687:Nuclear Proteins; D000255:Adenosine Triphosphate; D004247:DNA; D000076228:MRE11 Homologue Protein; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D045643:DNA Repair Enzymes
keywords: Atomic force microscopy; DNA break repair; MR(N) complex; RAD50 purification; Scanning force microscopy