Conformational properties of N-acetyl-N-methyl-alpha,beta-dehydroalanine N'-methylamide.
The conformational properties of Ac-Delta(Me)Ala-NHMe (N-acetyl-N-methyl-alpha,beta-dehydroalanine N'-methylamide), as the simplest model of N-methyl-alpha,beta-dehydroamino acids, was examined with theoretical methods and in comparison with Ac-DeltaAla-NHMe and Ac-DeltaAla-NMe(2). The N-terminal amide of the Delta(Me)Ala residue easily adopts the configuration cis and the torsion angles phi, psi are highly flexible. The Delta(Me)Ala residue is a conformational flexibilizer as compared to the parent DeltaAla, which is a conformational stiffener. This seems to be the reason why Delta(Me)Ala is found in small natural cyclic peptides, where it ensures the conformational flexibility necessary for biological action.
Macedowska
Agnieszka
A
Institute of Chemistry, University of Opole, Opole, Poland.
Siodłak
Dawid
D
Rzeszotarska
Barbara
B
D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry; D000577:Amides / Q000737:chemistry*; D001703:Biophysics / Q000379:methods; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry
D000577:Amides; C515312:N-acetyl-N-methyl-alpha,beta-dehydroalanine N'-methylamide; D010455:Peptides; D000409:Alanine