ectatomin (water solution, nmr 20 structures)
Ectatomin is a protein toxin from the venom of the ant Ectatomma tuberculatum. Ectatomin can efficiently insert into the plasma membrane, where it can form channels. Ectatomin was shown to inhibit L-type calcium currents in isolated rat cardiac myocytes. In these cells, ectatomin induces a gradual, irreversible increase in ion leakage across the membrane, which can lead to cell death.
Ectatomin is composed of two subunits, A and B, which are homologous. The structure of ectatomin reveals that each subunit consists of two alpha helices with a connecting hinge region, which form a hairpin structure that is stabilized by disulfide bridges. A disulfide bridge between the hinge regions of the two subunits links the heterodimer together, forming a closed bundle of four alpha helices with a left-handed twist.
- Pluzhnikov K, Nosyreva E, Shevchenko L, Kokoz Y, Schmalz D, Hucho F, Grishin E (June 1999). "Analysis of ectatomin action on cell membranes". Eur. J. Biochem. 262 (2): 501–6. doi:10.1046/j.1432-1327.1999.00426.x. PMID 10336635.
- Nolde DE, Sobol AG, Pluzhnikov KA, Grishin EV, Arseniev AS (January 1995). "Three-dimensional structure of ectatomin from Ectatomma tuberculatum ant venom". J. Biomol. NMR. 5 (1): 1–13. doi:10.1007/BF00227465. PMID 7881269.