| Popis: |
Lanthanide ion complexes of α-L-aspartyl-L-phenylalanine methyl ester have been characterized in the pH range 2.50-7.00. Proton resonance shifts in D2O and DMSO were used to determine the conformational mobility and a tentative structure in solution is proposed. The observed trends in the magnitude of the shift ratios and the rotamer population suggested that the metal ion Pr(III) or Dy(III) bound to the carboxylate group and gave information about the peptide backbone. The result of this analysis has been used to select a preferential conformation of the molecule: o1˜ 60d, φ2˜ -150d, CβCγLn = 140d± 10d, CαCβCγLn = 10d± 20d (hindered rotation), Cγ-Ln = 2.85Ad± 0.1Ad. |
