α-Synuclein is a key protein in neurodegenerative diseases. Its functions are modulated by multiple post-translational modifications that are poorly understood, including numerous truncated forms, which mass spectrometry must be able to characterize if the biological sample preparation is effective.
In a study published in Analytical Biochemistry, the LI-MS team (SPI/DMTS), in collaboration with the Pitié-Salpêtrière Hospital, improved the method of immunoprecipitation of α-synuclein from brain protein extracts by evaluating the key parameters influencing extraction yield and specificity, such as the capture antibody immobilization support (type of binding beads and quantity), the choice of antibody, and the elution conditions.
The optimized immunoprecipitation protocol was then combined with high-resolution mass spectrometry for the proteomic characterization of brain-derived α-synuclein from patients with Parkinson's disease and controls.
The analysis identified a total of 38 N- or C-terminally truncated forms of α-synuclein, including 22 novel sites.
The method as a whole constitutes a robust analytical tool for the reliable enrichment and characterization of α-synuclein from complex biological matrices. It paves the way for potential applications in biomarker discovery and the study of the pathogenic mechanisms of synucleinopathies. The diagnostic value of the newly identified forms of α-synuclein remains to be determined.
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