title: (alphaMe)Aun: a highly lipophilic, chiral, Calpha-tetrasubstituted alpha-amino acid. Incorporation into model peptides and preferred conformation.
abstract: Using a chemo-enzymatic approach we prepared the highly lipophilic, chiral, Calpha-methylated alpha-amino acid (alphaMe)Aun. Two series of terminally protected model peptides containing either D-(alphaMe)Aun in combination with Aib or L-(alphaMe)Aun in combination with Gly were synthesized using solution methods and fully characterized. A detailed solution conformational analysis, based on FT-IR absorption, 1H NMR and CD techniques, allowed us to determine the preferred conformation of this amino acid and the relationship between chirality at its alpha-carbon atom and screw sense of the helix that is formed. The results obtained strongly support the view that D-(alphaMe)Aun favors the formation of the left-handed 3(10)-helical conformation.
authors.affiliation: Department of Organic Chemistry, University of Padova, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Peggion
authors.forename: E
authors.initials: E
authors.lastname: Mossel
authors.forename: F
authors.initials: F
authors.lastname: Formaggio
authors.forename: M
authors.initials: M
authors.lastname: Crisma
authors.forename: B
authors.initials: B
authors.lastname: Kaptein
authors.forename: Q B
authors.initials: QB
authors.lastname: Broxterman
authors.forename: J
authors.initials: J
authors.lastname: Kamphuis
authors.forename: C
authors.initials: C
authors.lastname: Toniolo
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis*; D002942:Circular Dichroism; D003497:Cyclic N-Oxides; D004121:Dimethyl Sulfoxide; D005227:Fatty Acids / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives*; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000138:chemical synthesis*; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D014270:Trifluoroethanol
chemical_list: C406886:2-methyl-2-amino-undecanoic acid; D000596:Amino Acids; D003497:Cyclic N-Oxides; D005227:Fatty Acids; D009842:Oligopeptides; D014270:Trifluoroethanol; D005998:Glycine; C003959:TEMPO; D004121:Dimethyl Sulfoxide