Bernstein, Summer L. and Liu, Dengfeng and Wyttenbach, Thomas and Bowers, Michael T. and Lee, Jennifer C. and Gray, Harry B. and Winkler, Jay R. (2004) [alpha]-Synuclein: Stable compact and extended monomeric structures and pH dependence of dimer formation. Journal of the American Society for Mass Spectrometry, 15 (10). 1435 - 1443.
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Official URL: http://www.sciencedirect.com/science/article/B6TH2...
The protein α-synuclein, implicated in Parkinson's disease, was studied by combining nano-electrospray ionization (N-ESI) mass spectrometry and ion mobility. It was found that both the charge-state distribution in the mass spectra and the average protein shape deduced from ion mobility data, depend on the pH of the spray solution. Negative-ion N-ESI of pH 7 solutions yielded a broad charge-state distribution from −6 to −16, centered at −11, and ion mobility data consistent with extended protein structures. Data obtained for pH 2.5 solutions, on the other hand, showed a narrow charge-state distribution from −6 to −11, centered at −8, and ion mobilities in agreement with compact α-synuclein structures. The data indicated that there are two distinct families of structures: one consisting of relatively compact proteins with eight or less negative charges and one consisting of relatively extended structures with nine or more charges. The average cross section of a-synuclein at pH 2.5 is 33% smaller than for the extended protein sprayed from pH 7 solution. Significant dimer formation was observed when sprayed from pH 7 solution but no dimers were observed from the low pH solution. A plausible mechanism for aggregate formation in solution is proposed.
|Subjects:||Analytical Science > Metrology and standards in nanotechnology|
Biomedical Science > Nanomedicine
|Deposited On:||23 Jul 2009 16:52|
|Last Modified:||23 Jul 2009 16:52|
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