Ectatomin (1eci) is the main component of venom of the ant Ectatomma tuberculatum. When bitten by E. tuberculatum, Ectatomin inserts into the target's cell membranes and forms a nonselective cation channel.
Structure
Biologically, Ectatomin exists as a heterodimer stabilized by linkages. The α subunit has 37 amino acid residues, while the β subunit has 34 amino acid residues. The structure of Ectatomin was solved using 2D NMR and CHARMm computational optimization, though there are 20 similar proposed conformations.
Generally, each subunit is composed of two α-helices, linked by disulfide bonds, with a connecting hairpin hinge region. The two subunits are linked by a disfulide bond between their hairpin hinge regions. One α-helix from each subunit is kinked, due to the presence of proline residues. The kinked α-helix of the α subunit is more kinked, containing three proline residues, while the kinked α-helix of the β subunit only contains one proline residue.
The internal region between the two subunits is primarily composed of hydrophobic residues.
Sequence - α subunit
GVIPKKIWETVCPTVEPWAKKCSGDIATYIKRECGKL
Sequence - β subunit
WSTIVKLTICPTLKSMAKKCEGSIATMIKKKCDK
Mechanism
Toxicology
