Crystallographic Characterization of Helical Secondary Structures in α/β-Peptides with 1:1 Residue Alternation
作者:Soo Hyuk Choi、Ilia A. Guzei、Lara C. Spencer、Samuel H. Gellman
DOI:10.1021/ja800355p
日期:2008.5.1
on the type of helix formed and the stability of the helical conformation. On the basis of two-dimensional NMR data, we have previously proposed that beta-residues with a five-membered ring constraint promote two different types of alpha/beta-peptide helix. The "11-helix" contains i, i+3 CO...H-N hydrogen bonds between backbone amide groups; these hydrogen bonds occur in 11-atomrings. The alpha/beta-peptide
近来,几组研究表明,同时包含α-氨基酸和β-氨基酸残基(以1:1交替排列)的寡聚体在溶液中采用了螺旋二级结构。β-残基取代模式对形成的螺旋类型和螺旋构象的稳定性具有深远的影响。基于二维NMR数据,我们以前曾提出具有五元环约束的β-残基促进两种不同类型的α/β-肽螺旋。“ 11-螺旋”在主链酰胺基团之间包含i,i + 3 CO ... HN氢键;这些氢键出现在11个原子的环中。α/β-肽“ 14 / 15-螺旋”包含i,i + 4 CO ... HN氢键,它们以交替的14和15原子环出现。在这里,我们提供了形成11螺旋和/或14/15螺旋的14个alpha /β肽的晶体学数据。对于一系列含有衍生自(S,S)-反-2-氨基环戊烷酸(ACPC)的β-残基和衍生自α-氨基异丁酸(Aib)或1-丙氨酸(Ala)的α-残基的一系列低聚物,获得了这些结果。 。结晶的α/β-肽的长度范围为4至10个残基。
Crystallographic Characterization of the α/β-Peptide 14/15-Helix
作者:Soo Hyuk Choi、Ilia A. Guzei、Samuel H. Gellman
DOI:10.1021/ja0753344
日期:2007.11.1
We report the first high-resolution structural data for the 14/15-helix, a secondary structure that is formed by oligomers with a 1:1 alternation of α- and β-amino acid residues. Previously, we concluded from NMR data that short α/β-peptides containing cyclopentane-constrained β-residues display rapid interconversion between two helical folding patterns, the 11-helix (i,i+3 CO···H−N H-bonds) and the