title: C12 helices in long hybrid (αγ)n peptides composed entirely of unconstrained residues with proteinogenic side chains.
abstract: Unconstrained γ(4) amino acid residues derived by homologation of proteinogenic amino acids facilitate helical folding in hybrid (αγ)n sequences. The C12 helical conformation for the decapeptide, Boc-[Leu-γ(4)(R)Val]5-OMe, is established in crystals by X-ray diffraction. A regular C12 helix is demonstrated by NMR studies of the 18 residue peptide, Boc-[Leu-γ(4)(R)Val]9-OMe, and a designed 16 residue (αγ)n peptide, incorporating variable side chains. Unconstrained (αγ)n peptides show an unexpectedly high propensity for helical folding in long polypeptide sequences.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science , Bangalore, India , 560012.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Sonti
authors.forename: Bhimareddy
authors.initials: B
authors.lastname: Dinesh
authors.forename: Krishnayan
authors.initials: K
authors.lastname: Basuroy
authors.forename: Srinivasarao
authors.initials: S
authors.lastname: Raghothama
authors.forename: Narayanaswamy
authors.initials: N
authors.lastname: Shamala
authors.forename: Padmanabhan
authors.initials: P
authors.lastname: Balaram
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary
chemical_list: D000596:Amino Acids; D010455:Peptides