The discovery of functional RNAs that are critical for normal and disease physiology continues to expand at a breakneck pace. Many RNA functions are controlled by the formation of specific structures, and an understanding of each structural component is necessary to elucidate its function. Measuring solvent accessibility intracellularly with experimental ease is an unmet need in the field. Here, we present a novel method for probing nucleobase solvent accessibility, Light Activated Structural Examination of RNA (LASER). LASER depends on light activation of a small molecule, nicotinoyl azide (NAz), to measure solvent accessibility of purine nucleobases. In vitro, this technique accurately monitors solvent accessibility and identifies rapid structural changes resulting from ligand binding in a metabolite-responsive RNA. LASER probing can further identify cellular RNA–protein interactions and unique intracellular RNA structures. Our photoactivation technique provides an adaptable framework to structurally characterize solvent accessibility of RNA in many environments.

对正常和疾病生理学至关重要的功能性 RNA 的发现继续以惊人的速度扩展。许多 RNA 功能是由特定结构的形成控制的，了解每个结构成分对于阐明其功能是必要的。通过实验轻松测量细胞内溶剂的可及性是该领域尚未满足的需求。在这里，我们提出了一种探测核碱基溶剂可及性的新方法，即 RNA 光激活结构检查 (LASER)。激光依靠小分子烟酰叠氮化物 (NAz) 的光激活来测量嘌呤核碱基的溶剂可及性。在体外，该技术可准确监测溶剂可及性，并识别代谢物响应性 RNA 中配体结合导致的快速结构变化。激光探测可以进一步识别细胞 RNA-蛋白质相互作用和独特的细胞内 RNA 结构。我们的光活化技术提供了一个适应性强的框架，可以在结构上表征许多环境中 RNA 的溶剂可及性。