Supplementary Figure 3: Solution structure of the PfRad50HCC dimer and models for the ‘hook’ and ‘coiled-coil’ mutants.

(a) Molecular envelope of the PfRad50HCC dimer (residues 351-532) calculated from the SAXS data. (b) X-ray scattering profile of PfRad50HCC protein in solution, which was measured at 4°C. The open symbols are the experimental data and the solid line is the X-ray scattering profile. The Guinier plot of PfRad50HCC protein is shown in the inset. (c) Pair distance distribution p(r) function for PfRad50HCC protein, based on an analysis of the experimental SAXS data (empty circles) using the program GNOM⁵⁶. (d) A model for the SMC hinge mutant. T. maritima SMC hinge domain (residues 475 to 679, magenta and cyan) was fused to HsRad50 coiled-coils (585-651 and 714-766, blue and orange) at N- and C-terminal end, respectively. Detailed construct information is in Supplementary Table 4. (e) A Pfhook mutant dimer model. For FRET analysis, hook domain of PfRad50 (421-476, green and magenta for each monomer) is fused to 651-656 and 715-722 of HsRad50 at N- and C-terminal domain, respectively. (f) A Pfhook monomer model. The hook domain of PfRad50 (421-476, green) is fused to HsRad50 coiled-coils (585-656) and (715 to 766) at N- and C-terminal end, respectively. Gel filtration and ultracentrifuge analyses reveal that this construct favors monomer formation. (g) A model of coiled-coil deletion mutant of Rad50HCC182 (ΔCC mutant). Residues 614-668 and 702-750 are deleted. Residues (585-613, 751-766) of each monomer are shown in light blue and light orange, respectively, and junctions are marked.