title: Effect of central-residue replacements on the helical stability of a monomeric peptide.
abstract: The peptide acetylYEAAAKEARAKEAAAKAamide exhibits the dichroic features characteristic of a monomeric helix/coil transition in aqueous solution. Nineteen variants of this peptide each containing a different residue at position 9 were prepared by solid-phase peptide synthesis and purified by reversed-phase chromatography. The thermal dependence of the far-ultraviolet dichroic spectrum of each of these peptides except that containing proline is characteristic for an alpha-helix/coil transition. The relative stability of the helical forms of these peptides does not correlate with the preference of the variable amino acid to occupy a middle position in a protein helix. It is likely that the specific interactions of the variable residue with its local environment obscure any inherent preference of the residue to reside in an alpha-helix.
authors.affiliation: Department of Biochemistry, University of Iowa, Iowa City 52242.
authors.forename: G
authors.initials: G
authors.lastname: Merutka
authors.forename: W
authors.initials: W
authors.lastname: Lipton
authors.forename: W
authors.initials: W
authors.lastname: Shalongo
authors.forename: S H
authors.initials: SH
authors.lastname: Park
authors.forename: E
authors.initials: E
authors.lastname: Stellwagen
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D010455:Peptides; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D010455:Peptides