Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU), B Sarriena S/N, Campus UPV/EHU Leioa, Leioa, Vizcaya, Spain.
J Struct Biol. 2012 Nov;180(2):312-7. doi: 10.1016/j.jsb.2012.06.003. Epub 2012 Jun 21.
The recent high-resolution structure of the toxin FraC derived from the sea anemone Actinia fragacea has provided new insight into the mechanism of pore formation by actinoporins. In this work, we report two new crystal forms of FraC in its oligomeric prepore conformation. Together with the previously reported structure, these two new structures reveal that ring-like nonamers of the toxin assemble into compact two-dimensional hexagonal arrays. This supramolecular organization is maintained in different relative orientations adopted by the oligomers within the crystal layers. Analyses of the aggregation of FraC pores in both planar and curved (vesicles) model membranes show similar 2D hexagonal arrangements. Our observations support a model in which hexagonal pore-packing is a clustering mechanism that maximizes toxin-driven membrane damage in the target cell.
最近，从海葵 Actinia fragacea 中提取的毒素 FraC 的高分辨率结构为动质孔蛋白形成孔的机制提供了新的认识。在这项工作中，我们报告了 FraC 在其寡聚前孔构象中的两种新的晶体形式。与之前报道的结构一起，这两种新的结构表明，毒素的环状九聚体组装成紧密的二维六方排列。这种超分子组织在晶体层中寡聚物采用的不同相对取向中得以维持。FraC 孔在平面和弯曲（囊泡）模型膜中的聚集分析表明存在类似的 2D 六边形排列。我们的观察结果支持这样一种模型，即六边形孔堆积是一种聚类机制，可最大限度地增加靶细胞中毒素驱动的膜损伤。
