Macromolecular crowding effects on alpha-synuclein diffusion and conformational dynamics

Sina Heravi
MSc Student
Department of Biochemistry


Date: November 14, 2022
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Alpha-synuclein is an intrinsically disordered protein located in presynaptic neurons; it plays a leading role in vesicle and neurotransmitter release and regulation. In Parkinson's disease, the dysregulation and aggregation of alpha-synuclein lead to Lewy-body deposits and then cell death. The crowded environment inside living cells could be a major factor in alpha-synuclein aggregation. We evaluated the conformation of the alpha-synuclein in the presence of Ficoll70 as an artificial crowder and bacterial cell lysate as a biological crowder. We measured the diffusion of alpha-synuclein as diffusion is the primary mode of macromolecular transport inside the cell and can give an idea about the size of the alpha-synuclein. The results showed that alpha-synuclein diffuses faster in the cell lysate than in Ficoll70. However, cell lysate promotes aggregation faster than Ficoll70. The NMR data on alpha-synuclein's backbone mobility shows that the N terminal and NAC regions were more affected by lysate than the C terminal region. Also, we observed that the residues most affected by lysate crowder are hydrophobic amino acids. To probe the hydrophobic interactions, we reduced the hydrophobicity of the bacterial cell lysate. Following that, we observed that a few residues of alpha-synuclein behave differently than the way in the unmanipulated bacterial cell lysate. In summary, the results indicate the internal dynamics of the N terminal and NAC regions in the lysate crowder is faster than in the Ficoll70.