The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.
PLoS One. 2013 Sep 10;8(9):e74748. doi: 10.1371/journal.pone.0074748. eCollection 2013.
The structure of NheA, a component of the Bacillus cereus Nhe tripartite toxin, has been solved at 2.05 Å resolution using selenomethionine multiple-wavelength anomalous dispersion (MAD). The structure shows it to have a fold that is similar to the Bacillus cereus Hbl-B and E. coli ClyA toxins, and it is therefore a member of the ClyA superfamily of α-helical pore forming toxins (α-PFTs), although its head domain is significantly enlarged compared with those of ClyA or Hbl-B. The hydrophobic β-hairpin structure that is a characteristic of these toxins is replaced by an amphipathic β-hairpin connected to the main structure via a β-latch that is reminiscent of a similar structure in the β-PFT Staphylococcus aureus α-hemolysin. Taken together these results suggest that, although it is a member of an archetypal α-PFT family of toxins, NheA may be capable of forming a β rather than an α pore.
利用硒代蛋氨酸多波长反常散射（MAD）技术，解析了蜡样芽胞杆菌 Nhe 三联毒素的组成部分 NheA 的结构，分辨率为 2.05 Å。该结构表明，它具有与蜡样芽胞杆菌 Hbl-B 和大肠杆菌 ClyA 毒素相似的折叠结构，因此属于 ClyA 超家族的α-螺旋孔形成毒素（α-PFT），尽管与 ClyA 或 Hbl-B 相比，其头部结构明显增大。这些毒素的特征性疏水β发夹结构被一个两亲性β发夹取代，该β发夹通过β闩与主体结构相连，类似于β-PFT 金黄色葡萄球菌α-溶血素中的类似结构。综上所述，这些结果表明，尽管 NheA 是典型的α-PFT 家族毒素的成员，但它可能能够形成β孔而不是α孔。
