New tools for the control of peptide conformation and supramolecular chemistry: crown-carrier, C(alpha)-methyl L-DOPA amino acids.
The preferred conformation of five, terminally protected, model peptide series to the hexamer level, based on three novel crowned, C(alpha)-methyl L-DOPA amino acids combined with either L-Ala/Aib or Gly/Aib, were assessed in structure supporting solvents using FT-IR absorption, (1)H NMR, and CD techniques. The FT-IR absorption spectra strongly suggest that the contribution of the crowned C(alpha)-tetrasubstituted residue to intramolecular H-bonding is equivalent to that of Aib and is much more significant than that of either L-Ala or Gly. In addition, the (1)H NMR titrations and the CD patterns resemble those typically exhibited by (right-handed) 3(10)-helical structures.
Formaggio
Fernando
F
Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy. fernando.formaggio@unipd.it
Oancea
Simona
S
Peggion
Cristina
C
Crisma
Marco
M
Toniolo
Claudio
C
Wright
Karen
K
Wakselman
Michel
M
Mazaleyrat
Jean-Paul
JP
D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D000621:Aminoisobutyric Acids / Q000737:chemistry; D002942:Circular Dichroism; D007980:Levodopa / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
D000621:Aminoisobutyric Acids; D007980:Levodopa; D000409:Alanine