Haratake Mamoru, Takiguchi Tohru, Masuda Naho, Yoshida Sakura, Fuchigami Takeshi, Nakayama Morio
Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan.
Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
Colloids Surf B Biointerfaces. 2017 Jan 1;149:72-79. doi: 10.1016/j.colsurfb.2016.10.011. Epub 2016 Oct 7.
Sup35 is a prion-like protein from yeast and shares the ability to transmit its aberrant fold and to aggregate into amyloid fibrils. GNNQQNY from the prion-determining domain of Sup35 was reported to form an amyloid. We first investigated the self-aggregation transition behavior of GNNQQNY to the β-sheet amyloid state under various conditions. Mechanical stirring using a magnetic bar resulted in accelerated aggregation of the GNNQQNY. The aggregation rate of GNNQQNY was also dependent on its concentration; the higher the GNNQQNY concentration, the faster the aggregation. Circular dichroism and Fourier transform-infrared spectral data indicated the formation of the β-sheet structure in the GNNQQNY aggregates. The fluorescence experiments using an amyloid-specific thioflavin T also demonstrated that the GNNQQNY aggregates formed the amyloid structures. The amyloid structure of the GNNQQNY aggregates served as seeds for the elongation of the monomeric GNNQQNY in the solution state. We further studied the ability of the GNNQQNY amyloid fibrils to act as seeds for the elongation of the amyloid-forming monomeric proteins (albumin, lysozyme and insulin). The cross-seeding experiments suggested that the GNNQQNY aggregate could possibly promote the amyloid fibril formation of heterogeneous insulin. The inverse monomeric GNNQQNY would have a binding capacity for the heterogeneous already-formed amyloid-β fibrils on a mice brain section. These basic data could be informative for elucidating the pathogenic and/or propagation mechanisms of prion agents and developing effective therapeutics and/or diagnosis for prion diseases.
Sup35是一种来自酵母的类朊病毒蛋白，具有传递其异常折叠并聚集成淀粉样纤维的能力。据报道，Sup35朊病毒决定域中的GNNQQNY会形成淀粉样蛋白。我们首先研究了GNNQQNY在各种条件下向β-折叠淀粉样状态的自聚集转变行为。使用磁棒进行机械搅拌导致GNNQQNY的聚集加速。GNNQQNY的聚集速率也取决于其浓度；GNNQQNY浓度越高，聚集越快。圆二色性和傅里叶变换红外光谱数据表明GNNQQNY聚集体中形成了β-折叠结构。使用淀粉样特异性硫黄素T的荧光实验也证明GNNQQNY聚集体形成了淀粉样结构。GNNQQNY聚集体的淀粉样结构作为溶液状态下单体GNNQQNY延伸的种子。我们进一步研究了GNNQQNY淀粉样纤维作为淀粉样形成单体蛋白（白蛋白、溶菌酶和胰岛素）延伸种子的能力。交叉接种实验表明，GNNQQNY聚集体可能促进异源胰岛素的淀粉样纤维形成。反向单体GNNQQNY对小鼠脑切片上已形成的异源淀粉样β纤维具有结合能力。这些基础数据可能有助于阐明朊病毒因子的致病和/或传播机制，并开发针对朊病毒疾病的有效治疗方法和/或诊断方法。
