Loksztejn Anna, Dzwolak Wojciech
Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Biochemistry. 2009 Jun 9;48(22):4846-51. doi: 10.1021/bi900394b.
The enormous molecular weight complicates detailed structural studies of amyloid fibrils and obscures identification of biologically active forms of protein aggregates in amyloid-related diseases. Here we show that aqueous solutions of dimethyl sulfoxide (DMSO) solubilize insulin fibrils while maintaining their beta-pleated structure. This is accompanied by a marked decrease in the fluorescence of thioflavin T. According to atomic force microscopy images and dynamic light scattering measurements, the partial DMSO-induced dissection of insulin fibrils favors formation of smaller soluble oligomers, which retain a limited capacity to induce daughter generation of fibrils through seeding to the native insulin, as well as the ability to reassemble into fibrils upon removal of DMSO through dialysis against water. These findings suggest that the DMSO-induced ensembles of insulin molecules are closely related to elementary building blocks of amyloid fibrils.
巨大的分子量使淀粉样纤维的详细结构研究变得复杂，并模糊了淀粉样相关疾病中蛋白质聚集体生物活性形式的鉴定。在此我们表明，二甲基亚砜（DMSO）水溶液可溶解胰岛素纤维，同时保持其β折叠结构。这伴随着硫黄素T荧光的显著降低。根据原子力显微镜图像和动态光散射测量，DMSO对胰岛素纤维的部分解离有利于形成较小的可溶性寡聚体，这些寡聚体通过接种到天然胰岛素上诱导纤维的子代生成的能力有限，并且在通过对水进行透析去除DMSO后能够重新组装成纤维。这些发现表明，DMSO诱导的胰岛素分子聚集体与淀粉样纤维的基本构建块密切相关。
