Participation of non-aminoisobutyric acid (Aib) residues in the 3 10 helical conformation of Aib-rich foldamers: a solid state study
Participation of non-aminoisobutyric acid (Aib) residues in the 3 10 helical conformation of Aib-rich foldamers: a solid state study
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非氨基异丁酸 (Aib) 残基参与富含 Aib 的折叠体的 3 10 螺旋构象：固态研究
DOI：
10.1039/c4nj01547a
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发表时间：
2015
影响因子：
3.3
通讯作者：
Pike S
中科院分区：
文献类型：
--
作者：
Pike S
用X射线晶体学方法研究了一系列N-末端含有一个三级氨基酸的2-氨基异丁酸（Aib）折叠体（Cbz-L-苯丙氨酸（Cbz-L-Phe））的固态构象选择性。通过分析分子内氢键和肽扭转角确定了Aib折叠体N-末端的β-转角类型和整体螺旋-正义偏好。通过鉴定固态中采用的氢键基序，确定了C末端酯或酰胺对折叠体310螺旋构象的对比影响。类似地证实了链中间的非Aib非手性季铵残基稳定310螺旋的能力。结合这些结构特征，促进在Aib折叠体中形成连续的i → i + 3 β-转角，允许形成310螺旋构象的长链寡聚体，延伸超过21 π。
The solid state conformational preferences of a series of 2-aminoisobutyric acid (Aib) foldamers bearing a single N-terminal tertiary amino acid (Cbz-L-phenylalanine (Cbz-L-Phe)) have been investigated by X-ray crystallography. The type of β-turn present at the N-terminus and the global screw-sense preferences of the Aib foldamers were determined by analysis of intramolecular hydrogen-bonds and peptide torsion angles. The contrasting influence of a C-terminal ester or amide on the 310 helical conformation of the foldamers was established by identifying the hydrogen-bonding motifs adopted in the solid state. The ability of non-Aib achiral quaternary residues in the middle of the chain to stabilise the 310 helix was similarly confirmed. Combining these structural features, which promote the formation of consecutive i → i + 3 β-turns in Aib foldamers, permitted the formation of long chain oligomers in 310 helical conformations that extend over 21 Å.