Enhancement of ADP release from the RAD51 presynaptic filament by the SWI5-SFR1 complex |
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| Authors: | Guan-Chin Su Chan-I Chung Chia-Yu Liao Sheng-Wei Lin Cheng-Ting Tsai Tao Huang Hung-Wen Li Peter Chi |
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| Affiliation: | 1.Institute of Biochemical Sciences, National Taiwan University, NO. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, 2.Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 115, Taiwan and 3.Department of Chemistry, National Taiwan University, NO. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan |
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| Abstract: | Homologous recombination catalyzed by the RAD51 recombinase eliminates deleterious DNA lesions from the genome. In the presence of ATP, RAD51 forms a nucleoprotein filament on single-stranded DNA, termed the presynaptic filament, to initiate homologous recombination-mediated DNA double-strand break repair. The SWI5-SFR1 complex stabilizes the presynaptic filament and enhances its ability to mediate the homologous DNA pairing reaction. Here we characterize the RAD51 presynaptic filament stabilization function of the SWI5-SFR1 complex using optical tweezers. Biochemical experiments reveal that SWI5-SFR1 enhances ATP hydrolysis by single-stranded DNA-bound RAD51. Importantly, we show that SWI5-SFR1 acts by facilitating the release of ADP from the presynaptic filament. Our results thus provide mechanistic understanding of the function of SWI5-SFR1 in RAD51-mediated DNA recombination. |
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