A, schematic diagram of the At-N/Tg-C and Tg-N/At-C constructs. At-N/Tg-C represents domain swapping between the N-terminal 114 amino acids of AtSAT-c and C-terminal 198 amino acids of TgSAT-c, and Tg-N/At-C represents domain swapping between the N-terminal 113 amino acids of TgSAT-c and C-terminal 198 amino acids of AtSAT-c. White and black boxes, AtSAT-c and TgSAT-c, respectively. B, alignment of the predicted C-terminal amino acid sequences of TgSAT-c and AtSAT-c. Gray, identical amino acids; white, non-similar amino acid residues. Boxes indicate the amino acids used for the point-mutated SATs.