A Generalized Allosteric Mechanism for cis-Regulated Cyclic Nucleotide Binding Domains
Figure 3
The conserved N3A-motif in the N-terminal part of the α-subdomain.
(A) Stereo picture of N3A-motifs from 9 different CNB domains: A and B domains of PKA types RIα, RIIα, and RIIβ; Epac2; ionic channel HCN; and potassium channel MloK1. (B) Sequence alignment of the 9 N3A-motifs. α-helical regions are shaded magenta. Residues with negative chirality are shaded yellow. Hydrophobic residues or residues with large aliphatic segments are shown in bold. Colored circles correspond to the coloring on the stereo picture. (C) Hydrophobic interactions between residues of the N3A-motif provide integrity of the structural element. N3A-motif of PKA∶RIα A-domain is colored tan. Interacting residues are colored yellow. Connelly surfaces around their aliphatic parts are shown. (D) Residues on the tip of the 310-loop are involved in protein-protein interactions in the PKA holoenzyme. The PBC is colored cyan. C-subunit is colored grey.