SWI5 F83A/L85A-SFR1 is functionally impaired. ( A ) The effect of SWI5–SFR1 or SWI5 FL/AA –SFR1 on RAD51-mediated DNA strand exchange was examined. The results were graphed. ( B ) Exonuclease I protection assay was conducted with the indicated concentrations of SWI5–SFR1 and SWI5 FL/AA –SFR1. The results were graphed. ( C ) The average length of RAD51 filaments with negative staining was determined by electron microscopy (see Supplementary Figure S5). RAD51 was examined alone or with SWI5–SFR1 or SWI5 FL/AA –SFR1. The total 225 filaments were counted in each reaction. We note that the average length of the presynaptic filament in the presence of SWI5–SFR1 is much longer than expected. This could be due to the end-to-end association between two DNA molecules by RAD51 as described by Baumann et al. ( 35 ). ( D ) Thin-layer chromatography to monitor the hydrolysis of [γ- 32 P] ATP by RAD51 in the absence or presence of indicated concentrations of SWI5–SFR1 or SWI5 FL/AA –SFR1. The results were graphed. (A, B and D) Error bars represent the standard deviation (±SD) calculated based on at least three independent experiments.
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