Stable right- and left-handed peptide helices containing C(alpha)-tetrasubstituted alpha-amino acids.
Short peptidomimetics with stable secondary structures in solution are of interest for applications in chemistry, biology, and medicine. One way to rigidify the backbone of a peptide is the use of cyclic C(alpha)-tetrasubstituted alpha-amino acids (TAAs) like compound 14. The structures resulting from the incorporation of this unnatural amino acid into peptides were investigated. In total, 13 different peptides with a length of up to eight residues and alternating sequences of TAA 14 and (S)- or (R)-valine were synthesized. Their structures were characterized by X-ray diffraction analysis and NMR and CD measurements showing that the all-S-backbone-configured peptides 5 and 6 (SS)(2-3) form right-handed 3(10)-helices, while the all-R-configured peptides 11-13 (RR)(2-4) form left-handed 3(10)-helices in the solid state and solution.
Grauer
Andreas A
AA
Institute for Organic Chemistry, University of Regensburg, D-93040 Regensburg, Germany.
Cabrele
Chiara
C
Zabel
Manfred
M
König
Burkhard
B
D000596:Amino Acids / Q000737:chemistry*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D007536:Isomerism; D008958:Models, Molecular; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D017433:Protein Structure, Secondary
D000596:Amino Acids; D009842:Oligopeptides