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Published August 2009 | public
Journal Article

Deamidation of α-synuclein

Abstract

The rates of deamidation of α-synuclein and single Asn residues in 13 Asn-sequence mutants have been measured for 5 × 10^(-5)M protein in both the absence and presence of 10^(-2)M sodium dodecyl sulfate (SDS). In the course of these experiments, 370 quantitative protein deamidation measurements were performed and 37 deamidation rates were determined by ion cyclotron resonance Fourier transform mass spectrometry, using an improved whole protein isotopic envelope method and a mass defect method with both enzymatic and collision-induced fragmentation. The measured deamidation index of α-synuclein was found to be 0.23 for an overall deamidation half-time of 23 days, without or with SDS micelles, owing primarily to the deamidation of Asn(103) and Asn(122). Deamidation rates of 15 Asn residues in the wild-type and mutant proteins were found to be primary sequence controlled without SDS. However, the presence of SDS micelles slowed the deamidation rates of nine N-terminal region Asn residues, caused by the known three-dimensional structures induced through protein binding to SDS micelles.

Additional Information

© 2009 Wiley. Received: 19 April 2009; Revised: 27 May 2009; Accepted: 2 June 2009. Grant sponsors: John Kinsman Foundation, Morse Foundation, Ellison Medical Foundation.

Additional details

Created:
August 21, 2023
Modified:
October 18, 2023