We demonstrate a technique which can change the pH inside an NMR tube in steps of ≤0.01 pH unit, during a solution-state NMR experiment. We use a photo-acid co-solute with the actual specimen, and photo-excite the solution by direct fibre-mediated light delivery to the NMR tube. The photo-excitation and NMR measurements can be performed simultaneously. Our method should allow precise variation of the pH in studying protein folding, aggregation and enzyme catalysis processes which often display critical pH dependence.

中文翻译：

---

NMR光谱过程中精确的原位光致pH调节

我们证明了在溶液态NMR实验期间，可以以≤0.01pH单位的步长改变NMR管内pH的技术。我们将光酸共溶质与实际样品一起使用，并通过直接将纤维介导的光传输至NMR管而对溶液进行光激发。光激发和NMR测量可以同时进行。我们的方法应允许在研究蛋白质折叠，聚集和酶催化过程中精确地改变pH值，而蛋白质折叠，聚集和酶催化过程通常表现出关键的pH依赖性。