Wild-type yDna2 as well yDna2 E675A and yDna2 K1080E variants were expressed and purified as described previously (Levikova et al. 2013 (link)). The construct for the expression of the yDna2 ΔN variant was prepared by cloning the yDNA2 sequence lacking the first 1215 residues (corresponding to 405 amino acids) between the 5′-terminal Flag tag and the 3′-terminal 6His tag into BamHI and EcoRI sites in a pYes2 vector (Invitrogen). The truncated protein was expressed and purified as the full-length protein. Wild-type hDNA2, hDNA2 K654E, and hDNA2 K654R were prepared as described previously (Pinto et al. 2016 (link)). No difference was observed between the hDNA2 K654E and hDNA2 K654R variants in the experiments presented in this report (data not shown). Wild-type BLM, WRN, BLM K695A, and WRN K577M were expressed and purified as described (Pinto et al. 2016 (link)). Sgs1, Top3–Rmi1, and Mre11–Rad50–Xrs2 were expressed and purified as described previously (Cejka and Kowalczykowski 2010 (link); Cejka et al. 2010 (link); Cannavo and Cejka 2014 (link)). The yRPA and hRPA proteins were expressed and purified as described (Henricksen et al. 1994 (link); Kantake et al. 2003 (link)).