School of Life Sciences, University of Technology Sydney, Broadway, Building 4, Level 7, ROOM 340. Thomas Street, Ultimo, NSW, 2007, Australia.
Amino Acids. 2018 Apr;50(3-4):397-407. doi: 10.1007/s00726-017-2525-z. Epub 2017 Dec 12.
There is a strong body of evidence linking the non-protein amino acid (NPAA) β-methylamino-L-alanine (BMAA) to the development of a number of neurodegenerative diseases. BMAA has been found globally, is produced by a number of organisms including cyanobacteria, diatoms, and dinoflagellates; and has been shown to biomagnify through trophic levels. The role of BMAA in neurodegenerative disease is highlighted by its presence in the brains of a number of neurodegenerative disease patients, where it was found in a protein-bound form. We have previously shown that BMAA is bound to cell proteins, and results in the upregulation of the unfolded protein response, an endoplasmic reticulum stress response activated by the presence of misfolded proteins within the cell. Structurally aberrant proteins are features of a number of neurodegenerative diseases, and further investigation of how BMAA interacts with proteins is crucial to our understanding of its toxicity. Here we use radiolabelled BMAA to investigate the interaction and binding of BMAA to eukaryotic and prokaryotic proteins. We found differences in the presence and distribution of protein-bound BMAA between E. coli and neuroblastoma cells, with an increase in binding over time only seen in the eukaryotic cells. We also found that BMAA was unable to bind to pure proteins, or cell lysate in native or denaturing conditions, indicating that biological processing is required for BMAA to bind to proteins.
有大量证据表明，非蛋白氨基酸（NPAA）β-甲基氨基-L-丙氨酸（BMAA）与许多神经退行性疾病的发展有关。BMAA 已在全球范围内发现，由包括蓝藻、硅藻和甲藻在内的许多生物产生；并且已被证明通过营养级生物放大。BMAA 在神经退行性疾病中的作用是由其在许多神经退行性疾病患者的大脑中存在的事实所强调的，在那里它以蛋白结合的形式存在。我们之前已经表明，BMAA 与细胞蛋白结合，并导致未折叠蛋白反应的上调，这是一种内质网应激反应，由细胞内错误折叠的蛋白质的存在激活。结构异常的蛋白质是许多神经退行性疾病的特征，进一步研究 BMAA 如何与蛋白质相互作用对于我们理解其毒性至关重要。在这里，我们使用放射性标记的 BMAA 来研究 BMAA 与真核和原核蛋白质的相互作用和结合。我们发现，在大肠杆菌和神经母细胞瘤细胞中，蛋白结合的 BMAA 的存在和分布存在差异，只有在真核细胞中才会随着时间的推移而增加结合。我们还发现，BMAA 无法与纯蛋白质或天然或变性条件下的细胞裂解物结合，表明生物处理是 BMAA 与蛋白质结合所必需的。
