Figure 3. The design of TPR using RPS20.
RPS20-hh is identified by TPRpred to match the sequence profile of TPR units. Their structures are also very similar (helices are shown as cylinders), except for the last four residues (colored in light and dark magenta). We designed a TPR protein using a RPS20-hh with up to five mutations (yellow strips) in each repeat unit. The C-terminal loop in the TPR unit (dark magenta loop) is used to replace the corresponding C-terminus (light magenta cylinder) of RPS20-hh to connect adjacent repeats. The C-terminal helix in RPS20 (white cylinder) was used as the stop helix in the design.