Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
Pore-forming toxin
Pore-forming proteins (PFTs, also known as pore-forming toxins) are usually produced by bacteria, and include a number of protein exotoxins but may also be produced by other organisms such as apple snails that produce perivitellin-2 or earthworms, who produce lysenin. They are frequently cytotoxic (i.e., they kill cells), as they create unregulated pores in the membrane of targeted cells.
PFTs can be divided into two categories, depending on the alpha-helical or beta-barrel architecture of their transmembrane channel that can consist either of
Other categories:
According to TCDB, there are following families of pore-forming toxins:
β-PFTs are so-named because of their structural characteristics: they are composed mostly of β-strand-based domains. They have divergent sequences, and are classified by Pfam into a number of families including Leukocidins, Etx-Mtx2, Toxin-10, and aegerolysin. X-ray crystallographic structures have revealed some commonalities: α-hemolysin and Panton-Valentine leukocidin S are structurally related. Similarly, aerolysin and clostridial epsilon-toxin. and Mtx2 are linked in the Etx/Mtx2 family.
The ß-PFTs include a number of toxins of commercial interest for the control of pest insects. These toxins are potent but also highly specific to a limited range of target insects, making them safe biological control agents.
Insecticidal members of the Etx/Mtx2 family include Mtx2 and Mtx3 from Lysinibacillus sphaericus that can control mosquito vectors of human diseases and also Cry15, Cry23, Cry33, Cry38, Cry45, Cry51, Cry60, Cry64 and Cry74 from Bacillus thuringiensis that control a range of insect pests that can cause great losses to agriculture.
Insecticidal toxins in the Toxin_10 family show an overall similarity to the aerolysin and Etx/Mtx2 toxin structures but differ in two notable features. While all of these toxins feature a head domain and a larger, extended beta-sheet tail domain, in the Toxin_10 family, the head is formed exclusively from the N-terminal region of the primary amino acid sequence whereas regions from throughout the protein sequence contribute to the head domain in Etx/Mtx2 toxins. In addition, the head domains of the Toxin_10 proteins show lectin-like features of carbohydrate binding domains. The only reported natural targets of Toxin_10 proteins are insects. With the exception of Cry36 and Cry78, the Toxin_10 toxins appear to act as two-part, binary toxins. The partner proteins in these combinations may belong to different structural groups, depending on the individual toxin: two Toxin_10 proteins (BinA and BinB) act together in the Bin mosquitocidal toxin of Lysinibacillus sphaericus; the Toxin_10 Cry49 is co-dependent on the 3-domain toxin family member Cry48 for its activity against Culex mosquito larvae; and the Bacillus thuringiensis Toxin_10 protein Cry35 interacts with the aegerolysin family Cry34 to kill Western Corn Rootworm. This toxin pair has been included in insect resistant plants such as SmartStax corn.
Hub AI
Pore-forming toxin AI simulator
(@Pore-forming toxin_simulator)
Pore-forming toxin
Pore-forming proteins (PFTs, also known as pore-forming toxins) are usually produced by bacteria, and include a number of protein exotoxins but may also be produced by other organisms such as apple snails that produce perivitellin-2 or earthworms, who produce lysenin. They are frequently cytotoxic (i.e., they kill cells), as they create unregulated pores in the membrane of targeted cells.
PFTs can be divided into two categories, depending on the alpha-helical or beta-barrel architecture of their transmembrane channel that can consist either of
Other categories:
According to TCDB, there are following families of pore-forming toxins:
β-PFTs are so-named because of their structural characteristics: they are composed mostly of β-strand-based domains. They have divergent sequences, and are classified by Pfam into a number of families including Leukocidins, Etx-Mtx2, Toxin-10, and aegerolysin. X-ray crystallographic structures have revealed some commonalities: α-hemolysin and Panton-Valentine leukocidin S are structurally related. Similarly, aerolysin and clostridial epsilon-toxin. and Mtx2 are linked in the Etx/Mtx2 family.
The ß-PFTs include a number of toxins of commercial interest for the control of pest insects. These toxins are potent but also highly specific to a limited range of target insects, making them safe biological control agents.
Insecticidal members of the Etx/Mtx2 family include Mtx2 and Mtx3 from Lysinibacillus sphaericus that can control mosquito vectors of human diseases and also Cry15, Cry23, Cry33, Cry38, Cry45, Cry51, Cry60, Cry64 and Cry74 from Bacillus thuringiensis that control a range of insect pests that can cause great losses to agriculture.
Insecticidal toxins in the Toxin_10 family show an overall similarity to the aerolysin and Etx/Mtx2 toxin structures but differ in two notable features. While all of these toxins feature a head domain and a larger, extended beta-sheet tail domain, in the Toxin_10 family, the head is formed exclusively from the N-terminal region of the primary amino acid sequence whereas regions from throughout the protein sequence contribute to the head domain in Etx/Mtx2 toxins. In addition, the head domains of the Toxin_10 proteins show lectin-like features of carbohydrate binding domains. The only reported natural targets of Toxin_10 proteins are insects. With the exception of Cry36 and Cry78, the Toxin_10 toxins appear to act as two-part, binary toxins. The partner proteins in these combinations may belong to different structural groups, depending on the individual toxin: two Toxin_10 proteins (BinA and BinB) act together in the Bin mosquitocidal toxin of Lysinibacillus sphaericus; the Toxin_10 Cry49 is co-dependent on the 3-domain toxin family member Cry48 for its activity against Culex mosquito larvae; and the Bacillus thuringiensis Toxin_10 protein Cry35 interacts with the aegerolysin family Cry34 to kill Western Corn Rootworm. This toxin pair has been included in insect resistant plants such as SmartStax corn.