β-Sheet 13C structuring shifts appear only at the H-bonded sites of hairpins.
β-Sheet 13C structuring shifts appear only at the H-bonded sites of hairpins.
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β-Sheet 13C 结构变化仅出现在发夹的 H 键位点。
DOI：
10.1021/ja1088953
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发表时间：
2011
影响因子：
15
通讯作者：
Andersen,NielsH
中科院分区：
文献类型：
--
作者：
Shu,Irene;Stewart,JamesM;Scian,Michele;Kier,BrandonL;Andersen,NielsH
对设计的β-发夹测量的13 C化学位移表明，以前报道的用于诊断蛋白质中β-结构的结构位移（Cα和C′为高场，Cβ为低场）仅出现在氢键链残基处。然而，由此产生的结构位移幅度的周期性不是氢键状态的结果;相反，它反映了以前未被认识到的β链主链扭转角的变化。发夹的这种特征也可能存在于蛋白质中。该研究为β-结构中13 C位点的期望位移提供了参考值，这在β-折叠模型的折叠平衡表征中应该是有用的。
The13C chemical shifts measured for designed β-hairpins indicate that the structuring shifts (upfield for Cα and C′, downfield for Cβ) previously reported as diagnostic for β-structuring in proteins appear only at the H-bonded strand residues. The resulting periodicity of structuring shift magnitudes is not, however, a consequence of H-bonding status; rather, it reflects a previously unrecognized alternation in the backbone torsion angles of β-strands. This feature of hairpins is also likely to be present in proteins. The study provides reference values for the expectation shifts for13C sites in β-structures that should prove useful in the characterization of the folding equilibria of β-sheet models.