research papers
The structure of the synthetic protected oligopeptide Z-(Aib)9OBut, tert-butoxynona(α-aminoisobutyric acid), which contains the unusual α-aminoisobutyric acid (Aib), was determined by X-ray crystallography. The two independent molecules in the asymmetric unit fold into 310-helices, each stabilized by seven intramolecular hydrogen bonds. The C terminus of one of the molecules is disordered and adopts a semi-extended conformation, which is rather unusual for Aib residues. This is the first observation of such a conformation involved in a disorder in Aib-containing oligopeptides. The existence of a second conformation for the C-terminal residue might explain the difficulties in crystallizing the title compound and a different behaviour of the title compound in thin layer chromatography compared with the other homopeptides.
Supporting information
Crystallographic Information File (CIF) | |
Structure factor file (CIF format) |
CCDC reference: 131984