Identification of two sites of direct interaction between Cnn and PLP. (A) ClustalW multiple sequence alignment of the Cnn CM2 motif; similar (yellow) and identical (green) residues are shown. The asterisk shows an invariant arginine mutated in cnn^B4 mutants. (B) Graphic showing PLP and Cnn truncations used in Y2H. Two distinct interaction sites are shown. (C) Y2H assays for growth (left) and interaction (right; Materials and methods). (D) Graphic showing truncations of Cnn-F3 used for interaction refinement. The asterisk shows the R1141H mutation that mimics the cnn^B4 mutation.