Protein Folding and Dynamics Laboratory, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
Sci Rep. 2018 Apr 3;8(1):5481. doi: 10.1038/s41598-018-23718-3.
Aggregation of alpha synuclein has strong implications in Parkinson's disease. The heterogeneity of folding/aggregation landscape and transient nature of the early intermediates result in difficulty in developing a successful therapeutic intervention. Here we used fluorescence measurements at ensemble and single molecule resolution to study how the late and early events of alpha synuclein aggregation modulate each other. In-vitro aggregation data was complemented using measurements inside live neuroblastoma cells by employing a small molecule labeling technique. An inhibitor molecule (arginine), which delayed the late event of amyloidosis, was found to bind to the protein, shifting the early conformational fluctuations towards a compact state. In contrast, a facilitator of late aggregation (glutamate), was found to be excluded from the protein surface. The presence of glutamate was found to speed up the oligomer formation at the early stage. We found that the effects of the inhibitor and facilitator were additive and as a result they maintained a ratio at which they cancelled each other's influence on different stages of alpha synuclein aggregation.
α-突触核蛋白的聚集对帕金森病有重要影响。折叠/聚集景观的异质性和早期中间体的瞬态性质导致开发成功的治疗干预措施具有挑战性。在这里，我们使用荧光测量在整体和单分子分辨率来研究晚期和早期的α-突触核蛋白聚集事件如何相互调节。使用小分子标记技术在活神经母细胞瘤细胞内进行测量，补充了体外聚集数据。发现一种延迟淀粉样变性晚期事件的抑制剂分子（精氨酸）与蛋白质结合，使早期构象波动向紧凑状态转变。相比之下，促进晚期聚集的物质（谷氨酸）被发现被排除在蛋白质表面之外。发现谷氨酸的存在加速了早期寡聚体的形成。我们发现抑制剂和促进剂的作用是累加的，因此它们保持了一种比例，使它们在α-突触核蛋白聚集的不同阶段相互抵消影响。
