2013年5月12日訊 /生物谷BIOON/--蛋白質在人體內扮演著重要的角色，特別是神經蛋白，其在維持適當的腦功能中發揮關鍵作用。
腦部疾病如肌萎縮側索硬化症（ALS），阿爾茨海默氏症，帕金森氏被稱為「纏繞疾病」，因為上述疾病的特點是錯誤摺疊的蛋白纏繞、聚集在大腦中。
近日，科學家們發現一個不尋常的胺基酸--BMAA能插入到神經蛋白中，使神經蛋白發生錯誤摺疊和聚合。
BMAA是由一種光合細菌--藍藻產生的，BMAA已在ALS患者腦組織中被檢測到。在這篇發表在PLoS ONE雜誌上的研究論文中，研究者報告BMAA模仿一種膳食胺基酸--L-絲氨酸，誤納入到神經蛋白中，導致蛋白質錯誤摺疊。錯誤摺疊的蛋白質積聚在細胞，最終殺死它們。
更重要的是，科學家們發現，添加額外的L-絲氨酸到培養細胞中，可以防止BMAA進入到神經蛋白中。目前正在研究使用L-絲氨酸防止或延緩ALS的可能性。
儘管L-絲氨酸存在於我們的飲食中，但在通過FDA批准的臨床試驗之前，其對ALS患者的安全性和有效性應適當地被確定。（生物谷Bioon.com）
The Non-Protein Amino Acid BMAA Is Misincorporated into Human Proteins in Place of l-Serine Causing Protein Misfolding and Aggregation
Rachael Anne Dunlop,et al.
Mechanisms of protein misfolding are of increasing interest in the aetiology of neurodegenerative diseases characterized by protein aggregation and tangles including Amyotrophic Lateral Sclerosis (ALS), Alzheimer’s disease (AD), Parkinson’s disease (PD), Lewy Body Dementia (LBD), and Progressive Supranuclear Palsy (PSP). Some forms of neurodegenerative illness are associated with mutations in genes which control assembly of disease related proteins. For example, the mouse sticky mutation sti, which results in undetected mischarging of tRNAAla with serine resulting in the substitution of serine for alanine in proteins causes cerebellar Purkinje cell loss and ataxia in laboratory animals. Replacement of serine 422 with glutamic acid in tau increases the propensity of tau aggregation associated with neurodegeneration. However, the possibility that environmental factors can trigger abnormal folding in proteins remains relatively unexplored. We here report that a non-protein amino acid, β-N-methylamino-L-alanine (BMAA), can be misincorporated in place of L-serine into human proteins. We also report that this misincorporation can be inhibited by L-serine. Misincorporation of BMAA into human neuroproteins may shed light on putative associations between human exposure to BMAA produced by cyanobacteria and an increased incidence of ALS.