%0 Journal Article
%T Structural Domains of the Bacillus thuringiensis Vip3Af Protein Unraveled by Tryptic Digestion of Alanine Mutants
%J Toxins | An Open Access Journal from MDPI
%D 2019
%R https://doi.org/10.3390/toxins11060368
%X Vip3 proteins are increasingly used in insect control in transgenic crops. To shed light on the structure of these proteins, we used the approach of the trypsin fragmentation of mutants altering the conformation of the Vip3Af protein. From an alanine scanning of Vip3Af, we selected mutants with an altered proteolytic pattern. Based on protease digestion patterns, their effect on oligomer formation, and theoretical cleavage sites, we generated a map of the Vip3Af protein with five domains which match some of the domains proposed independently by two in silico models. Domain I ranges amino acids (aa) 12每198, domain II aa199每313, domain III aa314每526, domain IV aa527每668, and domain V aa669每788. The effect of some mutations on the ability to form a tetrameric molecule revealed that domains I每II are required for tetramerization, while domain V is not. The involvement of domain IV in the tetramer formation is not clear. Some mutations distributed from near the end of domain I up to the end of domain II affect the stability of the first three domains of the protein and destroy the tetrameric form upon trypsin treatment. Because of the high sequence similarity among Vip3 proteins, we propose that our domain map can be extended to the Vip3 family of proteins. View Full-Tex
%U https://www.mdpi.com/2072-6651/11/6/368