The Structural Characterization of Folded Peptides Containing the Conformationally Constrained<i>β</i>-Amino Acid Residue<i>β</i><sup>2,2</sup>Ac<sub>6</sub>c
作者:Krishnayan Basuroy、Vasantham Karuppiah、Narayanaswamy Shamala、Padmanabhan Balaram
DOI:10.1002/hlca.201200537
日期:2012.12
has been shown to result in a dramatic reduction in the conformational space that is sterically accessible to α‐amino acid residues in peptides. By extension, the presence of geminal dialkyl substituents at backbone atoms also restricts available conformational space for β and γ residues. Five peptides containing the achiral β2,2‐disubstituted β‐amino acid residue, 1‐(aminomethyl)cyclohexanecarboxylic
骨干烷基化已被证明导致在构象空间即空间上可接近到的显着降低α肽中氨基酸残基。通过扩展,在主链原子上双子烷基二烷基取代基的存在也限制了β和γ残基的可用构象空间。含有五种肽非手性β 2,2-二取代的β-氨基酸残基,1-(氨基甲基)环己烷羧酸(β 2,2- AC 6 c)所示,已被结构上由X射线衍射特征的晶体。三肽的Boc-Aib- β 2,2- AC 6的c-AIB-OME(1)采用了两个方向相反的分子内H键(C 11和C 9)稳定的新型折叠。所述四肽的Boc- [Aib- β 2,2- AC 6 C] 2 -OMe(2)和五肽的Boc- [Aib- β 2,2- AC 6 C] 2 -Aib-OME(3)形成杂交体的短链αβ ç 11螺旋分别稳定由两个和三个分子内氢键。二肽的Boc-Aib-的结构β 2,2- AC 6的c-OME(5)不会显示任何分子内H键。晶体中的聚合图案提供的伸展构象的一个例子β