Artículo del mes
noviembre 2021

Oligomerization of Sticholysins from Förster Resonance Energy Transfer

Referencia artículo:
Palacios-Ortega, J., Rivera-de-Torre, E., García-Linares, S., Gavilanes, J. G., Martínez-del-Pozo, A., & Slotte, J. P. (2021). Oligomerization of Sticholysins from Förster Resonance Energy Transfer. Biochemistry, 60(4), 314-323.
Las actinoporinas son unas de las toxinas del veneno de las anémonas marinas. Las esticolisinas (StnI y StnII) son las actinoporinas producidas por la anémona Stichodactyla helianthus. Estas toxinas forman poros en las membranas lipídicas, siempre que contengan esfingomielina. En este artículo hemos estudiado la estequiometría de los poros de las esticolisinas en solución y directamente en membranas modelo. Nuestros resultados indican que estas proteínas son capaces de oligomerizar en ausencia de membranas, que la estequiometría de los poros de esticolisina es de al menos siete oligómeros, y que la estequiometría es independiente de las isotoxinas que los formen.
Resumen
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.
Sobre el grupo investigador