Supplementary Figure 3: The STC is dimeric and contains disordered regions.

a, PONDR scores of predicted disordered regions. Disordered regions predicted with high confidence (indicated by black bars), are within the leucine zipper dimerization domain and the RNase H – CTD linker region. Contrary to the prediction results, we observe the dimerization domain to be largely ordered in the C1 reconstruction, in spite of the prediction suggesting that this region may undergo a disorder-to-order transition upon dimerization (Dunker, A. K. et al., J. Mol. Graph. Model. 19, 26–59, 2001). b, The disordered linker spanning the RNase H and CTD domains is represented by a red dashed line, with density for ordered regions colored by domain as in Fig. 2c. c, STC subunit organization. Densities are shown as in Fig. 2c but are colored by subunit (blue and green). Donor DNAs are colored in red, and target DNA in purple. The density corresponding to GTP is indicated in yellow.