Mechanism of Stabilization of Helical Conformations of Polypeptides by Water Containing Trifluoroethanol
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- 作者：Arthur Cammers-Goodwin ; Thomas J. Allen ; Sherri L. Oslick ; Kim F. McClure ; Janette H. Lee ; and D. S. Kemp
- 刊名：Journal of the American Chemical Society
- 出版年：1996
- 出版时间：April 3, 1996
- 年：1996
- 卷：118
- 期：13
- 页码：3082 - 3090
- 全文大小：270K
- 年卷期：v.118,no.13(April 3, 1996)
- ISSN：1520-5126
文摘
For conjugates Ac-Hel1-Alan-OH,n = 1-6, of the previously characterized reporting,conformationaltemplate Ac-Hel1, increases in helicity induced bytrifluoroethanol (TFE) in water have been related to asimplefunction of the peptide length n, yielding the helixpropagation constant sAla, which increases from1.0 to 1.5 for
fchars/chi.gif" BORDER=0 >TFE = 0-20 mol %. The per-residue helicityincrease is similar to the increase in te state stability induced byTFEin monoamide conjugates Ac-Hel1-NHR. Addition of TFEto water significantly increases the rate ofinterconversionof s-cis/s-trans amide conformers for Ac-Pro-NHMe, consistent with asignificant and selective destabilization ofthe planar resonance-stabilized amide. In dilute aqueous solutionTFE increases helicity by selectively destabilizingamide functions that are solvent exposed, with the consequence thatcompact conformations such as helices thatmaximize intramolecular amide-amide hydrogen bonding and minimizeamide solvent exposure are selectivelyfavored.
fchars/chi.gif" BORDER=0 >TFE = 0-20 mol %. The per-residue helicityincrease is similar to the increase in te state stability induced byTFEin monoamide conjugates Ac-Hel1-NHR. Addition of TFEto water significantly increases the rate ofinterconversionof s-cis/s-trans amide conformers for Ac-Pro-NHMe, consistent with asignificant and selective destabilization ofthe planar resonance-stabilized amide. In dilute aqueous solutionTFE increases helicity by selectively destabilizingamide functions that are solvent exposed, with the consequence thatcompact conformations such as helices thatmaximize intramolecular amide-amide hydrogen bonding and minimizeamide solvent exposure are selectivelyfavored.