Solution and solid state conformational preferences of a family of cyclic disulphide bridged tetrapeptides.
A set of cyclic tetrapeptides of the general form cyclo (Boc-Cys-Pro-X-Cys-OMe) with X being L-/D-Ala, L-/D-Val, and L-/D-Trp was synthesized. These peptides serve as model systems for structure elucidation in solution and feature a variety of structural motifs - namely a β-turn with intramolecular hydrogen bonding interactions, cis/trans isomerism, and a disulphide bond. In this work, we performed a comprehensive structural analysis focussing on their β-turn conformational preferences using NMR, VCD, and Raman spectroscopy. Our results provide evidence for a strong influence of a single stereocenter on the structures of the peptides whereas solvent polarity does not significantly affect them. Additionally, the solid state conformational preferences were studied by crystal structure analysis. Overall, a general trend for the conformational preferences of this set of peptides can be concluded from the results of the complementary investigations.
Fakultät für Chemie und Biochemie, Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum, 44801, Germany.
Nadja
N
Berger
Fakultät für Chemie und Biochemie, Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum, 44801, Germany.
Fee
F
Li
Fakultät für Chemie und Biochemie, Lehrstuhl für Anorganische Chemie, Ruhr-Universität Bochum, Bochum, 44801, Germany.
Bert
B
Mallick
Fakultät für Chemie und Biochemie, Lehrstuhl für Anorganische Chemie, Ruhr-Universität Bochum, Bochum, 44801, Germany.
J Thomas
JT
Brüggemann
Fakultät für Chemie und Biochemie, Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum, 44801, Germany. wolfram.sander@rub.de.
Wolfram
W
Sander
Fakultät für Chemie und Biochemie, Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum, 44801, Germany. christian.merten@rub.de.
Christian
C
Merten
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004220:Disulfides / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013059:Spectrum Analysis, Raman
D004220:Disulfides; D009842:Oligopeptides; D010456:Peptides, Cyclic
NOE analysis; cyclic peptides; secondary structure analysis; vibrational circular dichroism