A comparison of resultant fibrils upon environmental and sequential manipulations of α-synuclein, a Parkinson’s disease associated protein

α-Synuclein (AS) fibrils are the main component of Lewy bodies, filamentous inclusions known as the pathological hallmark of Parkinson’s disease (PD). The normal function, toxic state and detailed fibrillation pathway of AS are not well understood. However, AS is further implicated in PD by the presence of three single point mutations—A53T, A30P and E46K—and allele duplication or triplication in the familial form. One unifying difference between the single point mutations is their relative fibrillation rates; while E46K and A53T fibrillate more quickly, A30P fibrillates more slowly relative to the wild-type. Other factors that dictate the fibrillation rate of AS include: protein and salt concentration, agitation, temperature and pH. Therefore, carefully controlling fibrillation conditions is essential for making fair comparisons between wild-type AS fibrils and any sequential or environmental manipulations. This allows for the distinction between significant perturbations and slight differences from one sample batch to the next. Environmental manipulations of interest include: (1) the addition of metals and (2) a decrease of pH. Although there is no direct evidence linking metals to neurodegenerative diseases, evidence of elevated levels of metals are found in healthy aging brain and in brain of patients with neurodegenerative diseases. In addition, mitochondrial deficiencies and oxidative stress caused by cytosolic acidification have been associated with several PD cases. Several efforts have been made to identify the effects of these sequential and environmental manipulations; however, the techniques used were of low resolution or poor quality. Here, we have used the well-established, high-resolution methodologies of solid-state NMR to investigate the anomalies and differences between standard wild-type AS fibrils and those that have been sequentially or environmentally manipulated