Slow tert-butyl ester acidolysis and peptide 310-helix to α-helix transition in HFIP solution
✍ Scribed by Alessandro Moretto; Marco Crisma; Fernando Formaggio; Bernard Kaptein; Quirinus B. Broxterman; Timothy A. Keiderling; Claudio Toniolo
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2007
- Tongue
- English
- Weight
- 136 KB
- Volume
- 88
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
We have already shown by CD and NMR techniques that the terminally protected homo-octapeptides Z (and Ac)-[L-(aMe)Val] 8 -OtBu undergo a slow and irreversible 3 10 -helix to a-helix transition when dissolved in 1,1,1,3,3,3-hexafluoroisopropanol. In the present work, we find by HPLC and CD that under the aforementioned experimental conditions, a slow acidolysis of the tertbutyl ester functionality does take place affording the corresponding octapeptide free acids. The results of our combined chromatographic and spectroscopic experiments are confirmed by a comparison with the properties of independently synthesized and chemically characterized authentic compounds.