ИСТИНА

It has been demonstrated that β-peptides can adopt stable conformations resemble those of natural peptides, however, difference in the structure of the main chain chiral centers makes β-peptides inherently resistant to the proteolysis mediated by natural enzymes [1]. These peculiar properties of β-peptide molecules turn it to be very attractive objects for the drug design. Recently novel β-peptide homooligomer made of 5-methoxycarbonyl-2-phenylpyrrolidine monomers has been synthesized [2]. Steric control over the cycloaddition reaction allowed synthesis of the oligomers with a distinct alteration of pyrrolidine ring stereoisomers between adjacent monomeric units. Here we present solution-NMR study of 5-methoxycarbonyl-2-phenylpyrrolidine homooligomers. Installation of the bulky phenyl ring at Cα position and the ester group at Cδ results in formation of several conformers differ due to the peptide bond isomerization. Sufficient number of NMR-derived constraints collected allowed determining high-resolution structures for the observed conformations. Bibliography 1. Seebach, D., Overhand, M., Kuhnle, F. N. M., Martinoni, B., Oberer, L., Hommel, U. & Widmer, H. (1996) Beta-Peptides: Synthesis by Arndt-Eistert Homologation with Concomitant Peptide Coupling. Structure Determination by NMR and CD Spectroscopy and by X-Ray Crystallography. Helical Secondary Structure of a Beta-Hexapeptide in Solution and its Stability towards Pepsin., Helv Chim Acta. 79, 913–941. 2. Kudryavtsev, K. V., Ivantcova, P. M., Churakov, A. V., Wiedmann, S., Luy, B., Muhle-Goll, C., Zefirov, N. S. & Brase, S. (2013) Alternating asymmetric self-induction in functionalized pyrrolidine oligomers, Angewandte Chemie. 52, 12736-40.