Amino acid alignment of PKA-C subunit sequences from Schistosoma. Amino acid sequences of PKA-C subunits from Schistosoma mansoni (SmPKA-C; GQ168377), S. haematobium (ShPKA-C; GU116484), S. japonicum (SjPKA-C; GU130533) and Homo sapiens PKA-Cα (HsPKA-Ca; P17612), H. sapiens PKA-Cβ (HsPKA-Cb; P22694), and H. sapiens PKA-Cγ (HsPKA-Cg; P22612) were aligned using the ClustalW algorithm. Underlines indicate conserved amino acid sequences as follows: 1, kinase domain (Phe43 – Phe297); 2, ATP-binding site (Gly50 - Val57); 3, Ser/Thr active site (Arg165 - Asn171); 4, conserved autophosphorylation site (Thr196); 5, conserved sequence motif for PKA regulatory subunit binding (Leu198 - Tyr204).