Figure 3. β-layers in 6- and 9-residue motifs between GCN4 adaptors.
(A) The sequences and structures of the GCN4-fusion constructs are shown together with (B) a Ramachandran plot of their backbone torsion angles and (C, D) their periodicities. In the structures, the inserts between the GCN4 adaptors are drawn with thick lines. Disturbances in the α-helical segments are highlighted in pink; the stutter in the A6 structure and the stammer in the T96 structure are also highlighted in pink in panels C and D. In the periodicity plots, all proteins are aligned on the β-layer and their coiled-coil registers are indicated. The plots are shown separately for β-layers forming nonads (C) and hexads (D). A glitch in the periodicity caused by the g/c position preceding β-layers in hexads is highlighted in pink in panel D. As in the previous figure, the periodicity plots are smoothed over a three-residue sliding window. The Ramachandran plot in panel B includes all structures except the kinked grey A9b structure; all residues of the β-layers are shown as red dots and all other residues as black dots. Again, empty regions of the Ramachandran plot are cropped.