This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Sea Anemones Toxins
I. 5-8 kDa pore-forming, antihistaminicII. ~20 kDa pore-forming
Most numerous and most studied class:Equinatoxins II, IV and V (Actinia equina)Tenebrosins A, B and C (A. tenebrosa)Caritoxin (A. cari)Sticholysins StnI, StnII (Stichodactyla helianthus) and Smt (S. mertensii)Magnificalysins HgmIII, HetI and HetII (Heteractis magnifica)
Pores are formed by oligomers (tri- or tetramers)
High sequence homology within the actinoporin family, common structural properties
All monomeric, no Cys, rich in basic aminoacids
Equinatoxins
Equinatoxins
Sea Anemones Toxins
From Actinia equina L. (European sea anemone)
EqtI
EqtIIIEqtII
EqtIVEqtV
Equinatoxin II• -Sandwich structure,2 -helices on each side• N-terminal region (13-20) essential for cytolysis• Helix 1 is amphiphilic• Aromatic patch around W112 and W116, solvent-exposed
Equinatoxin II• -Sandwich structure,2 -helices on each side• N-terminal region (13-20) essential for cytolysis• Helix 1 is amphiphilic• Aromatic patch around W112 and W116, solvent-exposed
Equinatoxin II• -Sandwich structure,2 -helices on each side• N-terminal region (13-20) essential for cytolysis• Helix 1 is amphiphilic• Aromatic patch around W112 and W116, solvent-exposed
Equinatoxin II• -Sandwich structure,2 -helices on each side• N-terminal region (13-20) essential for cytolysis• Helix 1 is amphiphilic• Aromatic patch around W112 and W116, solvent-exposed
• Interaction EqtII-Binding to the membraneNo conformational change
• Interaction EqtII-PC/Insertion into the membrane Major conformational change
• Insertion at raft boundary? • Role of Cholesterol?