Lendel Christofer, Bertoncini Carlos W, Cremades Nunilo, Waudby Christopher A, Vendruscolo Michele, Dobson Christopher M, Schenk Dale, Christodoulou John, Toth Gergely
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Biochemistry. 2009 Sep 8;48(35):8322-34. doi: 10.1021/bi901285x.
Increasing evidence links the misfolding and aberrant self-assembly of proteins with the molecular events that underlie a range of neurodegenerative diseases, yet the mechanistical details of these processes are still poorly understood. The fact that many of these proteins are intrinsically unstructured makes it particularly challenging to develop strategies for discovering small molecule inhibitors of their aggregation. We present here a broad biophysical approach that enables us to characterize the mechanisms of interaction between alpha-synuclein, a protein whose aggregation is closely connected with Parkinson's disease, and two small molecules, Congo red and Lacmoid, which inhibit its fibrillization. Both compounds are found to interact with the N-terminal and central regions of the monomeric protein although with different binding mechanisms and affinities. The differences can be attributed to the chemical nature of the compounds as well as their abilities to self-associate. We further show that alpha-synuclein binding and aggregation inhibition are mediated by small oligomeric species of the compounds that interact with distinct regions of the monomeric protein. These findings provide potential explanations of the nonspecific antiamyloid effect observed for these compounds as well as important mechanistical information for future drug discovery efforts targeting the misfolding and aggregation of intrinsically unstructured proteins.
越来越多的证据表明，蛋白质的错误折叠和异常自组装与一系列神经退行性疾病背后的分子事件有关，但这些过程的机制细节仍知之甚少。这些蛋白质中有许多是内在无序的，这一事实使得开发发现其聚集的小分子抑制剂的策略特别具有挑战性。我们在此提出一种广泛的生物物理方法，该方法使我们能够表征α-突触核蛋白（一种其聚集与帕金森病密切相关的蛋白质）与两种小分子刚果红和焦油紫之间的相互作用机制，这两种小分子可抑制其纤维化。发现这两种化合物均与单体蛋白的N端和中央区域相互作用，尽管结合机制和亲和力不同。这些差异可归因于化合物的化学性质及其自缔合能力。我们进一步表明，α-突触核蛋白的结合和聚集抑制是由与单体蛋白不同区域相互作用的化合物的小寡聚体介导的。这些发现为这些化合物观察到的非特异性抗淀粉样蛋白效应提供了潜在解释，也为未来针对内在无序蛋白质的错误折叠和聚集的药物发现努力提供了重要的机制信息。
