Premium
The conformational properties of dehydrobutyrine and dehydrovaline: theoretical and solid‐state conformational studies
Author(s) -
Siodłak Dawid,
Grondys Justyna,
Lis Tadeusz,
Bujak Maciej,
Broda Małgorzata A.,
Rzeszotarska Barbara
Publication year - 2010
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.1267
Subject(s) - conformational isomerism , chemistry , solvent polarity , chloroform , polarity (international relations) , stereochemistry , alanine , crystallography , computational chemistry , solvent , molecule , amino acid , organic chemistry , biochemistry , cell
Abstract Dehydrobutyrine is the most naturally occurring dehydroamino acid. It is also the simplest dehydroamino acid having the geometrical isomers E / Z . To investigate its conformational properties, a theoretical analysis was performed on N ‐acetyl‐α,β‐dehydrobutyrine N ′‐methylamides, Ac‐( E )‐ΔAbu‐NHMe and Ac‐( Z )‐ΔAbu‐NHMe, as well as the dehydrovaline derivative Ac‐ΔVal‐NHMe. The ϕ, ψ potential energy surfaces and the localised conformers were calculated at the B3LYP/6‐311 + + G(d,p) level of theory both in vacuo and with inclusion of the solvent (chloroform, water) effect (SCRF method). The X‐ray crystal structures of Ac‐( Z )‐ΔAbu‐NHMe and Ac‐ΔVal‐NHMe were determined at 85 and 100 K, respectively. The solid‐state conformational preferences for the studied residues have been analysed and compared with the other related structures. Despite the limitations imposed by the C α = C β double bond on the topography of the side chains, the main chains of the studied dehydroamino acids are more flexible than in standard alanine. The studied dehydroamino acids differ in their conformational preferences, which depend on the polarity of the environment. This might be a reason why the nature quite precisely differentiates between ΔVal and each of the ΔAbu isomers, and why, particularly so with the latter, they are used as a conformational tool to influence the biological action of usually small, cyclic dehydropeptides. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.