NMR-Solution Structures in Methanol of an α-Heptapeptide, of a β3/β2-Nonapeptide, and of an all-β3-Icosapeptide Carrying the 20 Proteinogenic Side Chains
NMR-Solution Structures in Methanol of an α-Heptapeptide, of a β3/β2-Nonapeptide, and of an all-β3-Icosapeptide Carrying the 20 Proteinogenic Side Chains
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带有 20 条蛋白质侧链的 α-七肽、β3/β2-九肽和全 β3-二十肽在甲醇中的 NMR 溶液结构
DOI：
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
T. Etezady
中科院分区：
文献类型：
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作者：
D. Seebach;R. Mathad;T. Kimmerlin;Y. Mahajan;Pascal Bindschädler;M. Rueping;B. Jaun;C. Hilty;T. Etezady
研究了具有中心 Aib 残基的 α-七肽的 NMR 溶液结构，以验证与 β-肽相反，短 α-肽在 MeOH 中不会形成螺旋结构。尽管发现中心 Aib 残基会在实验确定的结构中引起弯曲，但没有发现较长 α 肽或蛋白质的典型二级结构。在 MeOH 和 H2O 中对具有极性、带正电侧链的 β2/β3-九肽进行 NMR 分析。然而，在 MeOH 中，它折叠成 10/12 螺旋，与仅具有脂肪族侧链的相应 β2/β3-九肽所确定的结构非常相似，但在 H2O 中无法确定主要构象。最后，描述了在 MeOH 中含有所有 20 种蛋白氨基酸侧链的 β3-二十碳肽的 NMR 分析。结果表明，这个 20 聚体在整个长度上折叠成 314 螺旋，形成六个完整的圈，这是迄今为止发现的最长的 314 螺旋。总之，我们的研究结果证实，与 α 肽相反，β 肽不仅形成仅具有六个残基的螺旋，而且形成的螺旋比通常在蛋白质或天然肽中观察到的螺旋部分更长。长β-肽较高的螺旋形成倾向归因于β-肽中交错乙烷部分的构象稳定作用，该作用超过了增加的巨偶极子的有害作用。
The NMR-solution structure of an α-heptapeptide with a central Aib residue was investigated in order to verify that, in contrast to β-peptides, short α-peptides do not form a helical structures in MeOH. Although the central Aib residue was found to induce a bend in the experimentally determined structure, no secondary structure typical for longer α-peptides or proteins was found. A β2/β3-nonapeptide with polar, positively charged side chains was subjected to NMR analysis in MeOH and H2O. Whereas, in MeOH, it folds into a 10/12-helix very similar to the structure determined for a corresponding β2/β3-nonapeptide with only aliphatic side chains, no dominant conformation could be determined in H2O. Finally, the NMR analysis of a β3-icosapeptide containing the side chains of all 20 proteinogenic amino acids in MeOH is described. It revealed that this 20mer folds into a 314-helix over its whole length forming six full turns, the longest 314-helix found so far. Together, our findings confirm that, in contrast to α-peptides, β-peptides not only form helices with just six residues, but also form helices that are longer than helical sections usually observed in proteins or natural peptides. The higher helix-forming propensity of long β-peptides is attributed to the conformation-stabilizing effect of the staggered ethane sections in β-peptides which outweighs the detrimental effect of the increasing macrodipole.
影响因子：
2.2
作者：
Schwieters, CD;Kuszewski, JJ;Clore, GM
通讯作者：
Clore, GM