title: Trapping a folding intermediate of the alpha-helix: stabilization of the pi-helix.
abstract: We report the design, synthesis, and characterization of a short peptide trapped in a pi-helix configuration. This high-energy conformation was nucleated by a preorganized pi-turn, which was obtained by replacing an N-terminal intramolecular main chain i and i + 5 hydrogen bond with a carbon-carbon bond. Our studies highlight the nucleation parameter as a key factor contributing to the relative instability of the pi-helix and allow us to estimate fundamental helix-coil transition parameters for this conformation.
authors.affiliation: Department of Chemistry, New York University, New York, New York 10003, USA.
authors.forename: Ross
authors.initials: R
authors.lastname: Chapman
authors.forename: John L
authors.initials: JL
authors.lastname: Kulp
authors.forename: Anupam
authors.initials: A
authors.lastname: Patgiri
authors.forename: Neville R
authors.initials: NR
authors.lastname: Kallenbach
authors.forename: Clay
authors.initials: C
authors.lastname: Bracken
authors.forename: Paramjit S
authors.initials: PS
authors.lastname: Arora
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: D010455:Peptides