RT Journal Article T1 Oligomerization of Sticholysins from Förster Resonance Energy Transfer A1 Palacios-Ortega, Juan A1 Rivera de la Torre, Esperanza A1 García-Linares, Sara A1 Gavilanes, José G. A1 Martínez Del Pozo, Álvaro A1 Slotte, J. Peter AB Sticholysins are pore-forming toxins produced by sea anemones that are members of the actinoporin family. They exert their activity by forming pores on membranes, provided they have sphingomyelin. To assemble into pores, specific recognition, binding, and oligomerization are required. While recognition and binding have been extensively studied, delving into the oligomerization process and the stoichiometry of the pores has been more difficult. Here, we present evidence that these toxins are capable of oligomerizing in solution and suggesting that the interaction of sticholysin II (StnII) with its isoform sticholysin I (StnI) is stronger than that of StnI with itself. We also show that the stoichiometry of the final, thermodynamically stable StnI pores is, at least, heptameric. Furthermore, our results indicate that this association maintains its oligomerization number when StnII is included, indicating that the stoichiometry of StnII is also of that order, and not tetrameric, as previously thought. These results are compatible with the stoichiometry observed for the crystallized pore of FraC, another very similar actinoporin produced by a different sea anemone species. Our results also indicate that the stoichiometry of actinoporin pores in equilibrium is conserved regardless of the particular composition of a given pore ensemble, which we have shown for mixed sticholysin pores. PB American Chemical Society SN 0006-2960; Electronic: 1520-4995 YR 2021 FD 2021-01-14 LK https://hdl.handle.net/20.500.14352/8070 UL https://hdl.handle.net/20.500.14352/8070 LA eng NO Universidad Complutense de Madrid/Banco de Santander NO Sigrid Juselius Foundation NO Jane and Aatos Erkko Foundation DS Docta Complutense RD 5 abr 2025