Fig 1.
SDS-PAGE analysis proteolytic digestion of protoxins by H. armigera larval midgut juice.
(A) The digestion of Cry1Ac protoxin. (B) The digestion of Cry2Ab protoxin. M, the BlueRay prestained protein marker (MDBio, Qingdao, China). Both protoxins were incubated with midgut juice at different midgut juice protein/protoxin ratios (total protein content of the gut juice added/5 μg protoxin protein) for 1 h at 37°C.
Fig 2.
The structure of Cry1Ac and Cry2Ab.
(A) The schematic diagram of Cry1Ac and Cry2Ab protoxins. The red dotted arrows represent cleavage sites. (B) Protein 3D structures of Cry1Ac protoxin and activated toxin. (C) Protein 3D structures of Cry2Ab protoxin and activated toxin. The three-dimensional structures of Cry1Ac and Cry2Ab protoxins were based on homologous modeling, built with SYBYL-Orchestrar software and viewed by the PyMOL program. The removed parts are shown in gray. The orange, green and purple represent domains I, II and III, respectively. Arg28 and Thr609 represent the cleavage sites of protease hydrolysis of Cry1Ac protoxin from the N- and C-termini, and Arg139 represents the cleavage sites of Cry2Ab from the N-terminus.
Table 1.
Toxicity of Cry1Ac and Cry2Ab protoxins and their respective midgut juice-digested toxins against neonates of the susceptible SCD strain of H. armigera.