Nano Archive

[alpha]-Synuclein: Stable compact and extended monomeric structures and pH dependence of dimer formation

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...

Abstract

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.

Item Type:Article
Subjects:Analytical Science > Metrology and standards in nanotechnology
Biomedical Science > Nanomedicine
ID Code:5782
Deposited By:SPI
Deposited On:23 Jul 2009 16:52
Last Modified:23 Jul 2009 16:52

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