Solid-state and solution-phase conformations of pseudoproline-containing dipeptides

Clegg, Jack K., Cochrane, James R., Sayyadi, Nima, Skropeta, Danielle, Turner, Peter and Jolliffe, Katrina A. (2009) Solid-state and solution-phase conformations of pseudoproline-containing dipeptides. Australian Journal of Chemistry, 62 7: 711-719. doi:10.1071/CH09151

Author Clegg, Jack K.
Cochrane, James R.
Sayyadi, Nima
Skropeta, Danielle
Turner, Peter
Jolliffe, Katrina A.
Title Solid-state and solution-phase conformations of pseudoproline-containing dipeptides
Journal name Australian Journal of Chemistry   Check publisher's open access policy
ISSN 0004-9425
Publication date 2009-01
Sub-type Article (original research)
DOI 10.1071/CH09151
Volume 62
Issue 7
Start page 711
End page 719
Total pages 9
Place of publication Collingwood, VIC, Australia
Publisher C S I R O Publishing
Language eng
Formatted abstract
The conformations of 14 threonine-derived pseudoproline-containing dipeptides (including four d-allo-Thr derivatives) have been investigated by NMR. In solution, the major conformer observed for all dipeptides is that in which the amide bond between the pseudoproline and the preceding amino acid is cis. For dipeptides in which the N-terminus is protected, the ratio of cis- to trans-conformers does not depend significantly on the side chain of the N-terminal amino acid, or the stereochemistry of the Thr residue. However, for dipeptides bearing a free N-terminus, there are significant differences in the ratios of cis- to trans-conformers depending on the side chain present. Three dipeptides were crystallized and their X-ray structures determined. In two cases, (benzyloxycarbonyl (Cbz)-Val-Thr(Me,Mepro)-OMe and Cbz-Val-Thr(Me,Mepro)-OH), the dipeptides adopt a trans-conformation in the solid state, in contrast to the structures observed in solution. In the third case, (9-fluorenylmethoxycarbonyl (Fmoc)-Val-d-allo-Thr( Me,Mepro)-OH), a cis-amide geometry is observed. These structural differences are attributed to crystal-packing interactions.
Keyword Pseudo prolines
Peptide synthesis
Building blocks
Amide bonds
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Published online: 13 July 2009.

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
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