Hydrogen bonds are essential for protein structure and function, making experimental access to long-range interactions between amide protons and heteroatoms invaluable. Here we show that measuring distance restraints involving backbone hydrogen atoms and carbonyl- or α-carbons enables the identification of secondary structure elements based on hydrogen bonds, provides long-range contacts and validates spectral assignments. To this end, we apply specifically tailored, proton-detected 3D (H)NCOH and (H)NCAH experiments under fast magic angle spinning (MAS) conditions to microcrystalline samples of SH3 and GB1. We observe through-space, semi-quantitative correlations between protein backbone carbon atoms and multiple amide protons, enabling us to determine hydrogen bonding patterns and thus to identify β-sheet topologies and α-helices in proteins. Our approach shows the value of fast MAS and suggests new routes in probing both secondary structure and the role of functionally-relevant protons in all targets of solid-state MAS NMR.

中文翻译：

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MAS NMR检测氢键进行蛋白质二级结构表征。

氢键对于蛋白质的结构和功能必不可少，因此使实验接近酰胺质子和杂原子之间的长距离相互作用非常重要。在这里，我们表明，测量涉及主链氢原子和羰基碳或α碳的距离限制可以基于氢键识别二级结构元素，提供远距离接触并验证光谱分配。为此，我们将特制的，质子检测的3D（H）NCOH和（H）NCAH实验在快速魔角旋转（MAS）条件下应用于SH3和GB1的微晶样品。我们观察到蛋白质主链碳原子与多个酰胺质子之间的空间，半定量相关性，从而使我们能够确定氢键模式，从而确定蛋白质中的β-折叠拓扑结构和α-螺旋。