Simultaneous monitoring of peptide aggregate distributions, structure, and kinetics using amide hydrogen exchange: Application to Aβ(1-40) fibrillogenesis
Article first published online: 27 FEB 2008
Copyright © 2008 Wiley Periodicals, Inc.
Biotechnology and Bioengineering
Volume 100, Issue 6, pages 1214–1227, 15 August 2008
How to Cite
Qi, W., Zhang, A., Patel, D., Lee, S., Harrington, J. L., Zhao, L., Schaefer, D., Good, T. A. and Fernandez, E. J. (2008), Simultaneous monitoring of peptide aggregate distributions, structure, and kinetics using amide hydrogen exchange: Application to Aβ(1-40) fibrillogenesis. Biotechnol. Bioeng., 100: 1214–1227. doi: 10.1002/bit.21846
- Issue published online: 13 JUN 2008
- Article first published online: 27 FEB 2008
- Accepted manuscript online: 27 FEB 2008 12:00AM EST
- Manuscript Accepted: 5 FEB 2008
- Manuscript Revised: 8 JAN 2008
- Manuscript Received: 17 OCT 2007
- amyloid beta protein (1-40);
- hydrogen exchange
Increasing evidence indicates that soluble aggregates of amyloid beta protein (Aβ) are neurotoxic. However, difficulty in isolating these unstable, dynamic species impedes studies of Aβ and other aggregating peptides and proteins. In this study, hydrogen–deuterium exchange (HX) detected by mass spectrometry (MS) was used to measure Aβ(1-40) aggregate distributions without purification or modification that might alter the aggregate structure or distribution. Different peaks in the mass spectra were assigned to monomer, low molecular weight oligomer, intermediate, and fibril based on HX labeling behavior and complementary assays. After 1 h labeling, the intermediates incorporated approximately ten more deuterons relative to fibrils, indicating a more solvent exposed structure of such intermediates. HX-MS also showed that the intermediate species dissociated much more slowly to monomer than did the very low molecular weight oligomers that were formed at very early times in Aβ aggregation. Atomic force microscopy (AFM) measurements revealed the intermediates were roughly spherical with relatively homogenous diameters of 30–50 nm. Quantitative analysis of the HX mass spectra showed that the amount of intermediate species was correlated with Aβ toxicity patterns reported in a previous study under the same conditions. This study also demonstrates the potential of the HX-MS approach to characterizing complex, multi-component oligomer distributions of aggregating peptides and proteins. Biotechnol. Bioeng. 2008;100: 1214–1227. © 2008 Wiley Periodicals, Inc.