No abstract

No abstract

The common feature of proteins involved in many neurodegenerative diseases is their ability to adopt at least two different stable conformations. The conformational transition that shifts the equilibrium from the functional, mostly partially alpha-helical structure, to the beta-sheet rich amyloid can be triggered by numerous factors, such as mutations in the primary structure or changes in the environment. We present a set of model peptides that, without changes in their primary structure, react in a predictable fashion in the presence of transition metal ions by adopting different conformations and aggregate morphologies. These de novo designed peptides strictly follow the characteristic heptad repeat of the alpha-helical coiled-coil structural motif. Furthermore, domains that favor beta-sheet formation have been incorporated to make the system prone to amyloid formation. As a third feature, histidine residues create sensitivity towards the presence of transition metal ions. CD spectroscopy, ThT fluorescence experiments, and transmission electron microscopy were used to characterize peptide conformation and aggregate morphology in the presence of Cu2+ and Zn2+. Furthermore, the binding geometry within peptide-Cu2+ complexes was characterized by electron paramagnetic resonance spectroscopy.

No abstract

Die Reaktion von [AuIII(mnt)2]− mit (n‐Bu4N)[BH4] in Aceton führt zur Bildung des bisher zweiten stabilen mononuklearen AuII‐Komplexes [AuII(mnt)2]2− dessen Struktur erstmals aufgeklärt werden konnte. (n‐Bu4N)2[AuII(mnt)2] kristallisiert triklin, P$\bar 1$ (a = 904,24(5), b = 989,55(5), c = 1627,35(10) pm, α = 92,040(7), β = 94,937(7), γ = 107,220(6)°, Z = 1) mit zwei Acetonmolekülen pro Elementarzelle. Das Anion ist planar. EPR‐Untersuchungen an Einkristallen von (n‐Bu4N)2[AuII(mnt)2] gestatten Aussagen zur Anisotropie des g‐Tensors und über die Linienbreitenanalyse Aussagen zu magnetischen Austauschwechselwirkungen.