Contact regions in the dimer of Alzheimer β-amyloid domain [1–28] studied by mass spectrometry

Information is provided about the amino acid residues in the [1–28] domain of the Alzheimer -amyloid protein, which participate in interstrand pairing and initiate fibillogenesis. The study was carried out using electrospray ionization on a four sector mass spectrometer, measuring kinetic energy release for a fragmentation process, and modeling the transition state with molecular dynamics calculations. The results eliminate the sequence [11–24] proposed earlier as the central core, and are consistent with, but do not distinguish between, residues [17–28] and [17–23] proposed by others based on biochemical studies.