title: 12/10- and 11/13-mixed helices in alpha/gamma- and beta/gamma-hybrid peptides containing C-linked carbo-gamma-amino acids with alternating alpha- and beta-amino acids.
abstract: New classes of alpha/gamma- and beta/gamma-hybrid peptides have been synthesized with novel 12/10- and 11/13-mixed helical patterns, respectively. The alpha/gamma-peptides were derived from the dipeptide repeats with alternating arrays of l-Ala and gamma-Caa((l)) (C-linked carbo-gamma-amino acid from d-mannose), which generated a new 12/10-mixed helix, for the first time, without a beta-amino acid. The beta/gamma-peptides made from an alternating arrangement of beta-Caa((x)) (C-linked carbo-beta-amino acid) and gamma-Caa((x)) (C-linked carbo-gamma-amino acid from d-xylose), on the other hand, resulted in an unprecedented 11/13-helix. The secondary structures in these peptides have been ascertained from detailed NMR studies, and CD spectroscopy and molecular dynamics investigations provided additional support for the structures derived.
authors.affiliation: Organic Chemistry Division III, D-211, Discovery Laboratory, and NMR Group, Indian Institute of Chemical Technology, Hyderabad 500,007, India. esmvee@iict.res.in
authors.forename: Gangavaram V M
authors.initials: GV
authors.lastname: Sharma
authors.forename: Vivekanand B
authors.initials: VB
authors.lastname: Jadhav
authors.forename: Kallaganti V S
authors.initials: KV
authors.lastname: Ramakrishna
authors.forename: Pagadala
authors.initials: P
authors.lastname: Jayaprakash
authors.forename: Kongari
authors.initials: K
authors.lastname: Narsimulu
authors.forename: Velaparthi
authors.initials: V
authors.lastname: Subash
authors.forename: Ajit C
authors.initials: AC
authors.lastname: Kunwar
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000596:Amino Acids; D010455:Peptides