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Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Orientation of spin labels in de novo peptides
Celine Elsässer1, Bernhard Monien, Wolfgang Haehnel
1Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany.
Abstract:
A series of de novo synthesised peptides including the artificial rigid paramagnetic amino acid TOAC at two positions with different distances from two to seven in the primary structure have been investigated by 9- and 94-GHz EPR spectroscopy under solid-state conditions. From simulations of the spectra of such two-spin systems, the distance and relative orientation of the paramagnetic centres can be deduced. This yields structural information on the peptides. A quantitative analysis of the spectra of individual peptides in different solvents as well as a qualitative analysis of the spectra of the peptide series shows that the peptides do not assume conformations corresponding to any of the common helical structures in proteins.
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