Overall structures of aaNAT2, aaNAT5b and paaNAT7 and 3D structural alignment of above three proteins and SNAT from O. aries. (A) Cartoon representation of aaNAT2. Motifs C, D, A, and B are labeled in purple, green, yellow, and red, respectively. Other regions of the structure are in gray. β-strands are numbered β1–β7. (B) Cartoon representation of aaNAT5b. The same scheme as used in A is used to color and label motifs, other parts of the structure, and β strands. (C) Cartoon representation of paaNAT7. The same scheme as used in A is used to color and label motifs and other parts of the structure. β strands are labeled β0–β7. (D) Superposition of the three mosquito aaNAT structures onto the structure of SNAT from O. aries. The same scheme as used in A is used to color and label motifs and β strands. Regions with major structural differences are colored gray for mosquito aaNATs and cyan for SNAT. (E) 3D structural alignment of aaNAT2, aaNAT5b, paaNAT7, and SNAT from O. aries (Oa-aaNAT). The second structures of SNAT are labeled under the sequences, and motifs C, D, A, and B are in purple, green, yellow, and red background boxes.