Thermodynamics Research Today is a free monthly online journal that collates and summarizes the latest research about Thermodynamics, including details on enthalpy, entropy, energy transitions.

Effects of Glycosylation of (2S,4R)-4-Hydroxyproline on the Conformation, Kinetics, and Thermodynamics of Prolyl Amide Isomerization.

Owens NW, Braun C, O'neil JD, Marat K, Schweizer F

Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada.

Glycosylation (galactosylation) of (2S,4R)-4-hydroxyproline (Hyp) in the peptide mimic N-acetyl-Hyp-N'-methylamide does not mediate the isomer equilibrium nor the rate of isomerization between the cis- and trans-prolyl amides in water. However, glycosylation of Hyp results in a downfield shift (6.5-8 ppm) of the Cgamma atom of proline that is consistent with an enhanced inductive effect. Moreover, NOE experiments on the alpha-and beta-linked glycosylated AcHypNHMe amides indicate proximity between the galactose and pyrrolidine rings. This study strongly suggests that glycosylation of Hyp will have important implications on peptide backbone conformation.

Published 19 September 2007 in J Am Chem Soc, 129(38): 11670-1.
Full-text of this article is available online (may require subscription).

© 2005-2008 Thermodynamics Research Today. All Rights Reserved.