Fig. 6. An Orthogonal CC basis set. (A) X-ray crystal structures and an AlphaFold2 (ref. 68) model for the assembled peptides in this set. The pentamer and heptamer were designed in this study, the other peptides have been published elsewhere.^30–33,59 The heat map shown in panel B represents the ideal case where all peptides are orthogonal to one another, i.e. only homotypic exchange is observed. Heat maps from the post-annealing fluorescence exchange data for the CC basis set (C) and the Orthogonal CC basis set (D) are shown side-by-side for comparison. The values in panel D indicate considerable orthogonality across the new set: the homotypic exchange (diagonal) values are all higher than those for any of the heterotypic exchange experiments (off-diagonal). All mixtures containing CC-Hept-IV-hen2 and/or FAM-CCHept-IV-hen2 were annealed to 75 °C instead of 95 °C as these peptides were not stable (with respect to precipitation) at the higher temperature (see Fig. S47†).