title: Stereochemical behavior of acyclic peptide-cation complexes.
abstract: The role of the beta-turns in the peptide interaction with several cations was investigated. In this work we report the solution studies of four linear peptides: Z-Aib-Aib-Aib-L-Val-OMe, Boc-D-aIle-L-Ile-D-aIle-L-Ile-OMe, Boc-L-Leu-L-Leu-L-Leu-L-Leu-OMe, and Boc-L-Phe-D-Phe-L-Phe-D-Phe-OMe. CD and 1H-nmr spectra reveal the presence of multiple ion-bonding equilibria. The stoichiometry and binding constant of the four peptides in the presence of Ca2+ ions in acetonitrile solution has been determined. Variable-temperature nmr spectra in the absence and in the presence of a large excess of cation have shown that the complexation process is not critically dependent on the conformation of the free peptide.
authors.affiliation: Dipartimento di Chimica, Università di Napoli, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Grimaldi
authors.forename: F
authors.initials: F
authors.lastname: Rossi
authors.forename: M
authors.initials: M
authors.lastname: Saviano
authors.forename: E
authors.initials: E
authors.lastname: Benedetti
authors.forename: V
authors.initials: V
authors.lastname: Pavone
authors.forename: C
authors.initials: C
authors.lastname: Pedone
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D002412:Cations; D010455:Peptides