Biochemical and Biophysical Research Communications, Vol.316, No.2, 393-397, 2004
Observation of multi-step conformation switching in beta-amyloid peptide aggregation by fluorescence resonance energy transfer
We have observed the conformation switching of Abeta(11-25) in the course of amyloid aggregation by employing time-resolved fluorescence resonance energy transfer (FRET). The amyloid peptides undergo multi-step conformational changes during self-assembling such as random coil (monomers), collapsed coil (multimers), micellar structure, and extended P-sheet in fibrils. We first identified the critical micelle concentration of Abeta(11-25) that occurs at ca. 3 muM for pH 5.0 and ca. 70 muM for pH 7.4. Our experimental results show clearly that the end-to-end distance of micellar Abeta(11-25) becomes much shorter than that of the collapsed coil or fibril structure. (C) 2004 Elsevier Inc. All rights reserved.