Synthesis and secondary conformations of homochiral β-oligopeptides containing aryl side chains

Abstract

A series of novel homochiral α-oligopeptides bearing aryl side chains was designed and synthesized from (S)-α-phenyl-α-amino acid derivatives by solution-phase methods. By means of circular dichroism(CD), Fouriertransform infrared spectrometry(FTIR), powder X-ray diffraction analysis(XRD) and density functional theory(DFT) calculations, we suggest that dipeptide P-2 and tripeptide P-3 adopt random coil-like conformations, pentapeptide P-5 and hexapeptide P-6 adopt stable 12-helix conformations in both solution and solid-state. Meanwhile, tetrapeptide P-4 adopt random coil-like conformation in solution and adopt 12-helix conformation in solid state.