Absence of secondary structure in a carbopeptoid tetramer of a trans-5-aminomethyl-tetrahydrofuran-2-carboxylate

Whereas trimers and tetramers of beta-C-D-arabinofuranosyl carbohydrate ami no acids adopt well defined conformations based around a repealing beta-tur n like structure, stabilised by (i, i-2) inter-residue hydrogen bonds, ther e is no indication of any secondary structure in the tetramer of the epimer ic alpha-C-D-arabinoluranosyl carbohydrate amino acid, where the C-2 and C- 5 substituents of the tetrahydrofuran ring are Irans to each other. (C) 199 9 Elsevier Science Ltd. All rights reserved.