The 3D-structure of 1a2kAD and multiple sequence alignment results of the 14 candidates to their corresponding template proteins of 1a2kAD. (A) A chain of 1a2k. The three important negatively charged residues, Glu42, Asp92 and Asp94, are colored by yellow. The C terminal peptide is colored by orange. (B) D chain of 1a2k. The switch II loops is colored by orange. (C) Alignment result of 1a2k A chain. Three important negative residues are marked in the yellow box. The hydrophobic peptide in C terminal is also an important interactive site (orange box). The red bars in the bottom are the contact positions in 1a2k A chain. (D) Alignment result of 1a2k D chain. The switch II loops are marked in orange box. The important aromatic residue Phe72 is marked by orange star. The red bars in the bottom are the contact positions in 1a2k D chain.