Fig. 4.

a Exploded view of the AgTEP1 TED-MG8 interface, highlighting distinct allotypes for the catalytic loop and the α3-α4 loop. b The crystal structure of the heterodimeric complex of LRIM1/APL1C, the helix-loop-helix (HLH) motif indicated by the boxed region. c Scale comparison of C3a, C5a and LRIM/APL1C HLH motif. d Current model of AgTEP1 regulation by LRIM1/APL1C. Short and long rounded rectangles represent the N- and C-terminal chains of TEP1, joined by a curved line representing the protease-sensitive, which is constitutively cleaved in the insect hemolymph. A yellow star indicates an intact thioester bond