Role of protein aggregation and interactions between α-synuclein and calbindin in Parkinson's disease

Parkinson's disease is one of the neurodegenerative diseases caused by protein aggregation. It has been reported that the proteins, α-synuclein and calbindin are related with Parkinson's disease. However, the interactions between these proteins and their relationship with protein aggregation prone regions have not yet been explored. In this work, we have systematically analyzed the characteristic features of amino acid residues in α-synuclein and calbindin, and obtained a structural model for the complex using protein docking procedures. The structural model of calbindin:α-synuclein complex structure was used to identify the binding site residues based on distance and energy based criteria. The aggregation prone regions in these proteins were identified using different computer programs and compared with binding site residues. Specific residues, which participate in aggregation and preventing calbindin-α-synuclein complex formation were explored and these residues may be main causes for Parkinson's disease. Further, we have carried out mutational analysis and estimated the energetic contributions of the aggregation prone regions towards stability. The results obtained in the present work would provide insights to understand the integrative role of protein-protein interactions and protein aggregation in Parkinson's disease and lead to new directions for inhibiting this disease. © 2013 Springer-Verlag.