The Chirality Chain in Valine: How the Configuration at the Cα Position through the O cis C'CαN Torsional System Leads to Distortion of the Planar Group CαC'(O cis )O trans to a Flat Tetrahedron

Henri Brunner; Takashi Tsuno

doi:10.1002/open.201800137

The Chirality Chain in Valine: How the Configuration at the C_α Position through the O _cis C'C_αN Torsional System Leads to Distortion of the Planar Group C_αC'(O _cis )O _trans to a Flat Tetrahedron

ChemistryOpen. 2018 Sep 3;7(9):696-700. doi: 10.1002/open.201800137. eCollection 2018 Sep.

Authors

Henri Brunner¹, Takashi Tsuno²

Affiliations

¹ Institut für Anorganische Chemie, Universität Regensburg 93040 Regensburg Germany.
² Department of Applied Molecular Chemistry College of Industrial Technology Nihon University, Narashino Chiba 275-8575 Japan.

Abstract

Solid-state structures, based on a Cambridge Structural Database (CSD) search, show that there is a C_αN/C'O _cis attraction in the torsional system O _cis C'C_αN of valine, causing a chirality chain. The C_α configuration controls the chirality of the rotation around the C'-C_α bond, which in turn induces a distortion of the planar unit C_αC'(O)O to a flat asymmetric tetrahedron. Conformational "reactions" take place in an energy profile with respect to clockwise and counterclockwise rotation around the C'-C_α bond as well as stretching and flattening of the tetrahedron. The molecular property C_αN/C'O _cis attraction of valine is maintained in its di- and tripeptides.

Keywords: amino acids; chirality; conformation; peptides; valine.