Fig. 3: Characterisation of Cdc20^N and its interaction with Mad1^CTD.

a ¹³C-detected 2D CON spectra of Cdc20^N alone (grey) and in the presence of Mad1^CTD (blue) at a four molar excess, shown with the assignment of Cdc20^N backbone resonances. b ¹³C-detected 2D CON spectra of Cdc20^N alone (grey) and in the presence of Mad1^CTDpT716 (red) at a twofold molar excess. c Relative peak intensities from the CON spectra of Cdc20^N in the presence of Mad1^CTD (blue) and Mad1^CTD pT716 (red) were mapped onto the Cdc20^N sequence. Peak intensities were normalised to the C-terminal residue Gly73. Regions showing significant line broadening coincide with regions that were predicted to be α-helical by both PSIPRED and AlphaFold2, as shown in the schematics above. d ¹⁵N{¹H}-heteronuclear NOE measuring the backbone dynamics in Cdc20^N and reported as mean values in technical duplicates. A higher (more positive) value indicates higher rigidity of the backbone amide bond, while a lower value indicates higher flexibility. e Secondary chemical shifts (∆δ¹³Cɑ) reveal residual secondary structure in Cdc20^N. Positive values suggest α-helical propensity and negative values suggest a propensity for β-strand conformation.