FIGURE 5.

BubR1 TPR domain exhibits both canonical and noncanonical packing interactions. A, TPR motif consensus sequence. B, interactions within BubR1 TPR motifs (panels i–iii) involving TPR consensus positions 4, 11, 8, 20, 24, and 27 (sticks). The angle between α-helices is noted. Superposition of the TPR motifs (panel iv) highlights the noncanonical packing of TPR2. C, packing between BubR1 TPR motifs (panels i–iv). Between TPR1 and TPR2, the canonical hydrophobic stacking of TPR consensus positions 7 and 24 (sticks) is replaced by ionic interactions (dotted lines). For all images, the N-terminal α-helix is yellow; TPR1 is green; TPR2 is red; TPR3 is blue, and the C-terminal α-helix is white.