Theoretical and Experimental Studies on α/ε-Hybrid Peptides: Design of a 14/12-Helix from Peptides with Alternating (S)-C-Linked Carbo-ε-amino Acid [(S)-ε-Caa(x)
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- 作者：Gangavaram V. M. Sharma ; Bommagani Shoban Babu ; Deepak Chatterjee ; Kallaganti V. S. Ramakrishna ; Ajit C. Kunwar ; Peter Schramm ; Hans-Jrg Hofmann
- 刊名：Journal of Organic Chemistry
- 出版年：2009
- 出版时间：September 4, 2009
- 年：2009
- 卷：74
- 期：17
- 页码：6703-6713
- 全文大小：1091K
- 年卷期：v.74,no.17(September 4, 2009)
- ISSN：1520-6904
文摘
An (S)-C-linked carbo-ε-amino acid [(S)-ε-Caa(x)] was prepared from the known (S)-δ-Caa. This monomer was utilized together with l-Ala to give novel α/ε-hybrid peptides in 1:1 alternation. Conformational analysis on penta- and hexapeptides by NMR (in CDCl3), CD, and MD studies led to the identification of robust 14/12-mixed helices. This is in agreement with the data from a theoretical conformational analysis on the basis of ab initio MO theory providing a complete overview on all formally possible hydrogen-bonded helix patterns of α/ε-hybrid peptides with 1:1 backbone alternation. The “new motif” of a mixed 14/12-helix was predicted as most stable in vacuum. Obviously, the formation of ordered secondary structures is also possible in peptide foldamers with amino acid constituents of considerable backbone lengths. Thus, α/ε-hybrid peptides expand the domain of foldamers and allow the introduction of desired functionalities via the α-amino acid constituents.