Unique structural features of aaNAT2, aaNAT5b, and paaNAT7. (A–C) Unique structural features between β3 and β4 strands of aaNAT2 (A), aaNAT5b (B), and paaNAT7 (C). (D) Superposition of 15 GNAT structures, including aaNAT2, aaNAT5b, and paaNAT7. Only the three mosquito aaNATs have this unique helix/helices structural feature; the other 12 GNATs, representing different HATs, different AACs, different GNATs, and SNAT shown in Fig. 3, do not have this structural feature.