Figure EV4. Mad1^CTD‐Bub1^CD1 asymmetry and differential Bub1^CD1 occupancy are conserved across structures from different space groups.

1. Alignment of Mad1^CTD‐Bub1^CD1 structure from the P2₁2₁2 space group (PDB: 7B1J). Left panel: Alignment of opposite subunits of the homodimer on the RLK site. Right panel: Alignment of opposite subunits on the head domain. The duplicated dimers are coloured in orange or blue.
2. Electron density map of the Mad1^CTD‐Bub1^CD1 structure from the P2₁2₁2 space group (PDB: 7B1J) visualized in Coot (Emsley et al, 2010) which shows near equivalent peptide occupancy. The Mad1^CTD homodimer is represented as a ribbon in orange and yellow.
3. Alignment of one homodimer from the Mad1^CTD‐Bub1^CD1 structure from the P2₁ space group (PDB: 7B1H). Left panel: Alignment of opposite subunits of the homodimer on the RLK site. Right panel: Alignment of opposite subunits on the head domain. The duplicated dimers are coloured in orange or blue.
4. Alignment of the second homodimer from the Mad1^CTD‐Bub1^CD1 structure from the P2₁ space group (PDB: 7B1H). Left panel: Alignment of opposite subunits of the homodimer on the RLK site. Right panel: Alignment of opposite subunits on the head domain. The duplicated dimers are coloured in orange or blue.
5. Electron density map of one homodimer from the Mad1^CTD‐Bub1^CD1 structure (shown directly above) from P2₁ space group visualized in Coot (Emsley et al, 2010). The Mad1^CTD homodimer is represented as a ribbon in green and yellow.
6. Electron density map of the second homodimer from the Mad1^CTD‐Bub1^CD1 structure (shown directly above) from the P2₁ space group visualized in Coot (Emsley et al, 2010). The Mad1^CTD homodimer is represented as a ribbon in pink and blue. The occupancy of the peptide on the right is extremely poor as is the density for the head domain it contacts.
7. All four Mad1^CTD homodimers from the three different space group structures are aligned onto their Mad1^CTD RLK motif which is bound to the higher occupancy peptide. Blue = homodimer_1 from P2₁. Orange = homodimer_2 from P2₁. Purple = P2₁2₁2₁ homodimer. Black = P2₁2₁2.

Source data are available online for this figure.