Browsing by Author "Vogel, A."
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- ItemThe influence of the Δk280 mutation and N- or C-terminal extensions on the structure, dynamics, and fibril morphology of the tau R2 repeat(London [u.a.] : Royal Society of Chemistry, 2014) Raz, Y.; Adler, J.; Vogel, A.; Scheidt, H.A.; Häupl, T.; Abel, B.; Huster, D.; Miller, Y.Tau is a microtubule-associated protein and is involved in microtubule assembly and stabilization. It consists of four repeats that bind to the microtubule. The ΔK280 deletion mutation in the tau R2 repeat region is directly associated with the development of the frontotemporal dementia parkinsonism linked to chromosome 17 (FTDP-17). This deletion mutation is known to accelerate tau R2 repeat aggregation. However, the secondary and the tertiary structures of the self-assembled ΔK280 tau R2 repeat mutant aggregates are still controversial. Moreover, it is unclear whether extensions by one residue in the N- or the C-terminus of this mutant can influence the secondary or the tertiary structure. Herein, we combine solid-state NMR, atomic force microscopy, electron microscopy and all-atom explicit molecular dynamics simulations to investigate the effects of the deletion mutation and the N- and the C-terminal extension of this mutant on the structure. Our main findings show that the deletion mutation induces the formation of small aggregates, such as oligomers, and reduces the formation of fibrils. However, the extensions in the N- or the C-terminus revealed more fibril formation than small aggregates. Further, in the deletion mutation only one structure is preferred, while the N- and the C-terminal extensions strongly lead to polymorphic states. Finally, our broad and combined experimental and computational techniques provide direct structural information regarding ΔK280 tau R2 repeat mutant aggregates and their extensions in the N- and C-terminii by one residue.
- ItemVariation of Ice Nucleating Particles in the European Arctic Over the Last Centuries(Hoboken, NJ [u.a.] : Wiley, 2019) Hartmann, M.; Blunier, T.; Brügger, S.O.; Schmale, J.; Schwikowski, M.; Vogel, A.; Wex, H.; Stratmann, F.The historical development of ice nucleating particle concentrations (NINP) is still unknown. Here, we present for the first time NINP from the past 500 years at two Arctic sites derived from ice core samples. The samples originate from the EUROCORE ice core (Summit, Central Greenland) and from the Lomo09 ice core (Lomonosovfonna, Svalbard). No long-term trend is obvious in the measured samples, and the overall range of NINP is comparable to present-day observations. We observe that the short-term variations in NINP is larger than the long-term variability, but neither anthropogenic pollution nor volcanic eruptions seem to have influenced NINP in the measured temperature range. Shape and onset temperature of several INP spectra suggest that INP of biogenic origin contributed to the Arctic INP population throughout the past. ©2019. The Authors.