Rtt107 physically interacted with the SMC5/6 complex. A, Rtt107-TAP but not Slx4-TAP co-immunoprecipitated with Nse5-FLAG independently of exposure to 0.025% MMS for 2 h. Analytical-scale TAP purifications were performed on whole cell extracts of the indicated strains. Immunoblotting was performed using anti-rabbit IgG or anti-FLAG antibodies. B, Rtt107-TAP co-immunoprecipitated with Nse5-FLAG independently of Slx4. C, separate pools of Rtt107 interacted with Slx4 or SMC5/6. Eluates from large-scale TAP purifications were subsequently immunoprecipitated with anti-FLAG or anti-HA-agarose beads. Immunoblotting was performed using anti-rabbit IgG, anti-HA, or anti-FLAG antibodies. D, the N-terminal portion of Rtt107 was responsible for the interaction with Nse5-FLAG. The truncation mutants of Rtt107 were from Roberts et al. (5).