Figure 4
Characterization of the CDC73 K34Q mutant and analysis of the differences between CDC73(1–111) and CDC73(1–100). (a) CD spectra of the CDC73(1–111) K34Q mutant, with wild-type (WT) and the del(5–10) mutant as positive and negative controls, respectively. (b) Thermofluor assays reveal a Tm difference of 10 °C for both WT vs K34Q CDC73(1–111) and CDC73(1–111) vs CDC73(1–100). The left panel shows the fluorescence change corresponding to temperature. The right panel is the calculation of melting temperatures. (c) In our crystal structure, the K34 sidechain (with dual conformations observed) forms salt bridges with D23 and D58. (d) Positions of residues 5–10 in the CDC73 H1 helix, shown in orange in the structure. Internal deletion of these 6 residues disrupts the overall fold of hCDC73-NTD. (e) The CDC73-NTD C-terminal tail (residues 101–111) interacts with the rest of CDC73-NTD via hydrogen bonds and van der Waals forces. CDC73(1–100) and the C-terminal tail are shown in cyan and green, respectively. The hydrogen bonds between them are labeled with yellow dash.
