Toxic principle of selva ant venom is a pore-forming protein transformer.
Ectatomin (Ea) is a newly isolated main toxic component of Ectatomma tuberculatum ant venom. Structural and electrophysiological studies were performed with purified Ea. The protein consists of two homologous polypeptide chains (37 and 34 residues) and forms a four alpha-helix bundle in aqueous solution. On insertion into artificial bilayer membranes, two Ea molecules form an ion pore. Our results suggest that the 'inside-out' mechanism of pore formation requires a significant movement of Ea helical parts. The pore formation in the cell membrane might well explain the toxic activity of Ea, not excluding at the same time its intracellular activities.
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
A S
AS
Arseniev
K A
KA
Pluzhnikov
D E
DE
Nolde
A G
AG
Sobol
Torgov MYu
S V
SV
Sukhanov
E V
EV
Grishin
D000595:Amino Acid Sequence; D000818:Animals; D000862:Ant Venoms / Q000737:chemistry* / Q000494:pharmacology / Q000633:toxicity; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003058:Cockroaches / Q000187:drug effects; D004594:Electrophysiology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017385:Sequence Homology
D000862:Ant Venoms; C088426:ectatomin protein, Ectatomma tuberculatum