Conformational properties of N-acetyl-N-methyl-α,β-dehydroalanine N’-methylamide*
نویسندگان
چکیده
The conformational properties of Ac-∆(Me)Ala-NHMe (N-acetyl-N-methyl-α,β-dehydroalanine N’methylamide), as the simplest model of N-methyl-α,β-dehydroamino acids, was examined with theoretical methods and in comparison with Ac-∆Ala-NHMe and Ac-∆Ala-NMe2. The N-terminal amide of the ∆(Me)Ala residue easily adopts the configuration cis and the torsion angles φ, ψ are highly flexible. The ∆(Me)Ala residue is a conformational flexibilizer as compared to the parent ∆Ala, which is a conformational stiffener. This seems to be the reason why ∆(Me)Ala is found in small natural cyclic peptides, where it ensures the conformational flexibility necessary for biological action.
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