title: New helical folds in α-peptides with alternating chirality.
abstract: In α-peptides, the 8/10 helix is theoretically predicted to be energetically unstable and has not been experimentally observed so far. Based on our earlier studies on 'helical induction' and 'hybrid helices', we have adopted the 'end-capping' strategy to induce the 8/10 helix in α-peptides by using short α/β-peptides. Thus, α-peptides containing a regular string of α-amino acids with alternating chirality were end capped by α/β-peptides with 11/9-helical motifs at the termini. Extensive NMR spectroscopy studies of these peptides revealed the presence of a hitherto unknown 8/10-helical pattern; the H-bonds in the shorter pseudorings were rather weak. The approach of using short helical motifs to induce new mixed helices in α-peptides could provide avenues for more versatile design strategies.
authors: Organic and Biomolecular Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007 (India). esmvee@iict.res.in.
authors: Gangavaram V M
authors: GV
authors: Sharma
authors: Gajulapati
authors: G
authors: Venkateshwarlu
authors: Pothula Purushotham
authors: PP
authors: Reddy
authors: Ajit C
authors: AC
authors: Kunwar
mesh_terms: D000595:Amino Acid Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013237:Stereoisomerism
chemical_list: D010455:Peptides
keywords: chirality; helical induction; helical structures; hybrid structures; peptides