FIGURE 5.

Comparison of the cAMP-binding domains in the known structures of PKA orthologues. A, schematic representation of the A- or CBD1 cAMP-binding site from B. taurus-type RIα (25). Helices within CBD1 are colored aquamarine, and those within CBD2 teal, and the bound cAMP is shown in red. The interdomain interfacial hydrophobic capping tryptophan contributed by αA′ is shown in stick representation. Similar representations are presented for the CBD1 domains of PfPKA-R (B) and RnPKA-RIIβ (C) (26). Similar representations of the CBD2 domains are presented for BtPKA-RIα (D). E, PfPKA-R; F, RnPKA-RIIβ. Yellow arrows indicate the orthologue structures to which each malarial PfPKA-R binding domain is most similar.