2014 年 56 巻 2 号 p. 133-138
The RecQ family of DNA helicases play a key role in protecting the genome against deleterious changes. In humans, mutations in the members WRN (Werner syndrome protein) and BLM (Bloom syndrome protein) respectively lead to rare genetic diseases associated with accelerated aging and cancer predisposition. Recently we determined the 3D structures of human WRN and BLM including a crystal structure of the RecQ C-terminal (RQC) domain bound to a DNA duplex, the first structure of the RecQ-DNA complex. In the complex, the β-wing of the RQC winged-helix motif acts as a scalpel to induce unpairing of a Watson-Crick base pair, an explanation for the unique activities of RecQs toward recombination and repair intermediates such as Holliday junctions.