title: Structural versatility of peptides containing C alpha, alpha-dialkylated glycines: conformational energy computations, i.r. absorption and 1H n.m.r. analysis of 1-aminocyclopropane-1-carboxylic acid homopeptides.
abstract: Conformational energy computations on the 1-aminocyclopropane-1-carboxylic acid mono-, di-, and tripeptide amides, Ac-(Ac3c)n-NHMe (n = 1-3), indicate that this C alpha, alpha-dialkylated, cyclic alpha-amino acid residue is conformally restricted and that type-I(I') beta-bends and distorted 3(10)-helices are particularly stable conformations for the di- and tripeptide amides, respectively. The results of the theoretical analysis are in agreement with those obtained in an i.r. absorption and 1H n.m.r. investigation in chloroform solution of Ac3c-rich tri- and tetrapeptide esters. A comparison is also made with the conclusions extracted from our previous work on peptides rich in Aib (alpha-aminoisobutyric acid), Ac5c (1-aminocyclopentane-1-carboxylic acid), and Ac6c (1-aminocyclohexane-1-carboxylic acid).
authors.affiliation: Department of Organic Chemistry, University of Padua, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Crisma
authors.forename: G M
authors.initials: GM
authors.lastname: Bonora
authors.forename: C
authors.initials: C
authors.lastname: Toniolo
authors.forename: V
authors.initials: V
authors.lastname: Barone
authors.forename: E
authors.initials: E
authors.lastname: Benedetti
authors.forename: B
authors.initials: B
authors.lastname: Di Blasio
authors.forename: V
authors.initials: V
authors.lastname: Pavone
authors.forename: C
authors.initials: C
authors.lastname: Pedone
authors.forename: A
authors.initials: A
authors.lastname: Santini
authors.forename: F
authors.initials: F
authors.lastname: Fraternali
mesh_terms: D000478:Alkylation; D000596:Amino Acids / Q000737:chemistry*; D000598:Amino Acids, Cyclic; D005998:Glycine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared
chemical_list: D000596:Amino Acids; D000598:Amino Acids, Cyclic; D009842:Oligopeptides; C023863:1-aminocyclopropane-1-carboxylic acid; D005998:Glycine