Delta endotoxin
Encyclopedia
Delta endotoxins are pore-forming toxins produced by Bacillus thuringiensis
species of bacteria. They are useful for their insecticidal
action.
During spore
formation the bacteria produce crystals of this protein. When an insect ingests these proteins, they are activated by proteolytic cleavage. The N-terminus is cleaved in all of the proteins and a C-terminal extension is cleaved in some members. Once activated, the endotoxin binds to the gut epithelium and causes cell lysis by the formation of cation-selective channels, which leads to death. The activated region of the delta toxin is composed of three distinct structural domains: an N-terminal helical bundle domain involved in membrane insertion and pore formation; a beta-sheet central domain involved in receptor binding; and a C-terminal beta-sandwich domain that interacts with the N-terminal domain to form a channel.
Bacillus thuringiensis
Bacillus thuringiensis is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide; alternatively, the Cry toxin may be extracted and used as a pesticide. B...
species of bacteria. They are useful for their insecticidal
Insecticidal
Insecticidal is a 2005 [Horror Thriller featuring giant, killer insects. A college student is modifying insects until a housemate tries to kill them...
action.
During spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
formation the bacteria produce crystals of this protein. When an insect ingests these proteins, they are activated by proteolytic cleavage. The N-terminus is cleaved in all of the proteins and a C-terminal extension is cleaved in some members. Once activated, the endotoxin binds to the gut epithelium and causes cell lysis by the formation of cation-selective channels, which leads to death. The activated region of the delta toxin is composed of three distinct structural domains: an N-terminal helical bundle domain involved in membrane insertion and pore formation; a beta-sheet central domain involved in receptor binding; and a C-terminal beta-sandwich domain that interacts with the N-terminal domain to form a channel.