Institute of Theoretical and Experimental Biophysics RAS, Institutskaya st., 3, Russia.
Institute of Protein Research RAS, Institutskaya st., 4, Russia.
Biochem Biophys Res Commun. 2020 Apr 2;524(2):453-458. doi: 10.1016/j.bbrc.2020.01.113. Epub 2020 Jan 29.
In most cases high cytotoxicity is characteristic of aggregates formed during lag phase of amyloid formation, whereas mature fibrils represent the depot of protein molecules incapable of damaging cell membranes. However, new experimental data show that in cases of some proteins the fibrils are the most toxic type of aggregates. Meanwhile, structural characteristics of cytotoxic fibrils and mechanisms of their cell damaging action are insufficiently explored. This work is dedicated to studying amyloid aggregation of bovine carbonic anhydrase (BCA) and effect of aggregates formed at different stages of amyloid formation on viability of the cells. Here we demonstrate that oligomers formed during lag phase do not decrease cell viability, whereas protofibrils and amyloids of BCA are cytotoxic. Obtained results allow concluding that toxicity of BCA aggregates is associated with the presence of amyloid cross-β-structure, which signature is absorbance peak at low wavenumbers at FTIR spectra (1615-1630 cm). Our data suppose that cross-β-core of ВСА amyloid fibrils is responsible for their cytotoxicity.
在大多数情况下，高细胞毒性是在淀粉样形成的迟滞期形成的聚集体的特征，而成熟的纤维则代表了不能破坏细胞膜的蛋白质分子的储存库。然而，新的实验数据表明，在某些蛋白质的情况下，纤维是最具毒性的聚集类型。同时，细胞毒性纤维的结构特征及其破坏细胞的作用机制尚未得到充分研究。这项工作致力于研究牛碳酸酐酶（BCA）的淀粉样聚集以及在淀粉样形成的不同阶段形成的聚集体对细胞活力的影响。在这里，我们证明了在迟滞期形成的低聚物不会降低细胞活力，而原纤维和 BCA 的淀粉样物是细胞毒性的。得出的结果表明，BCA 聚集体的毒性与淀粉样交叉-β-结构的存在有关，其特征是在傅里叶变换红外光谱（FTIR）谱（1615-1630 cm）中在低波数处出现吸收峰。我们的数据表明，BCA 淀粉样纤维的交叉-β-核心负责其细胞毒性。
