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Figure 1
(a) XANES pre-edge spectra of [{\rm A}\beta_{4-16_{z}}(z = 1,2,3)], [{\rm A}\beta_{4-12_{1}}] and [{\rm A}\beta_{4-8_{z}}(z = 1,2)] peptides highlighting the region relating to the 1s–3d transition. These three shorter peptides appear to have the same structure for copper binding. There appears to be no radiation photoreduction during the collection of data. By comparing these [{\rm A}\beta_{4-y_{z}}](y = 8, 12, 16 and z = 1, 2, 3) spectra with the spectrum of Aβ1–16 peptide, it is clear that these Aβ4–y peptides do not have a structure similar to Aβ1–16 for copper binding. (b) The expanded pre-edge region of Aβ1–16 peptide showing a weak pre-edge peak at 8978 eV and Aβ4–16/12/8 peptides showing possible weak pre-edge peaks at 8979 eV. The (forbidden) 1s–3d region is affected by geometry and, for example, dihedral angles.

IUCrJ
Volume 11| Part 3| May 2024| Pages 325-346
ISSN: 2052-2525
https://doi.org/10.1107/S2052252524001830