Hyperpolarization through signal amplification by reversible exchange (SABRE) provides a facile means to enhance nuclear magnetic resonance (NMR) signals of small molecules containing an N-heterocycle or other binding site for a polarization transfer catalyst. A purpose-designed reporter ligand, which is capable of binding both to a target protein and to the catalyst, makes the sensitivity enhancement by this technique compatible with the measurement of a range of biomolecular interactions. The ¹H polarization of the reporter ligand 4-amidinopyridine, which is targeting trypsin, is used to screen ligands that are not themselves hyperpolarizable by SABRE. The respective protein–ligand dissociation constants (K_D) are determined by an observed change in the R₂ relaxation rate of the reporter. A calculation of expected signal changes indicates that the accessible ligand K_D values extend over several orders of magnitude, while the concentrations of target proteins and ligands can be reduced considering the sensitivity gains from hyperpolarization. In general, the design of a single, weakly binding ligand for a target protein enables the use of SABRE hyperpolarization for ligand screening or other biophysical studies involving macromolecular interactions.

中文翻译：

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使用 SABRE 超极化报告基因筛选蛋白质-配体结合

通过可逆交换信号放大实现超极化 (SABRE) 提供了一种简便的方法来增强包含 N-杂环或其他极化转移催化剂结合位点的小分子的核磁共振 (NMR) 信号。一种专门设计的报告配体，能够与靶蛋白和催化剂结合，通过这种技术提高灵敏度，与测量一系列生物分子相互作用相兼容。靶向胰蛋白酶的报告配体 4-脒基吡啶的^{1 H 极化用于筛选本身不能被 SABRE 超极化的配体。}各自的蛋白质-配体解离常数 ( K _D ) 由观察到的R变化决定₂记者的放松率。对预期信号变化的计算表明，可接近的配体K _D值扩展了几个数量级，而考虑到超极化的灵敏度增益，可以降低靶蛋白和配体的浓度。一般来说，针对靶蛋白设计单一的弱结合配体，可以使用 SABRE 超极化进行配体筛选或其他涉及大分子相互作用的生物物理研究。