20826341 , Related PDB id: 3MXN
- Hoadley KA, Xu D, Xue Y, Satyshur KA, Wang W, Keck JL
- Structure and cellular roles of the RMI core complex from the bloom syndrome dissolvasome.
- Structure. 2010 Sep 8;18(9):1149-58.
- BLM, the protein product of the gene mutated in Bloom syndrome, is one of five human RecQ helicases. It functions to separate double Holliday junction DNA without genetic exchange as a component of the "dissolvasome," which also includes topoisomerase IIIalpha and the RMI (RecQ-mediated genome instability) subcomplex (RMI1 and RMI2). We describe the crystal structure of the RMI core complex, comprising RMI2 and the C-terminal OB domain of RMI1. The overall RMI core structure strongly resembles two-thirds of the trimerization core of the eukaryotic single-stranded DNA-binding protein, Replication Protein A. Immunoprecipitation experiments with RMI2 variants confirm key interactions that stabilize the RMI core interface. Disruption of this interface leads to a dramatic increase in cellular sister chromatid exchange events similar to that seen in BLM-deficient cells. The RMI core interface is therefore crucial for BLM dissolvasome assembly and may have additional cellular roles as a docking hub for other proteins.