Biotin is a common functional handle for bioconjugation to proteins and DNA, but its uses are limited to protein-containing conjugation partners such as streptavidin and derivatives thereof. Recently, oxaziridine reagents were developed that selectively conjugate the thioether of methionines on the surface of proteins, a method termed redox-activated chemical tagging (ReACT). These reagents generate sulfimide linkages that range in stability depending on the solvent accessibility and substitutions on the oxaziridine. Here we show that oxaziridine reagents react rapidly with the thioether in biotin to produce sulfimide products that are stable for more than 10 d at 37 °C. This method, which we call biotin redox-activated chemical tagging (BioReACT), expands the utility of biotin labeling and enables a predictable and stable chemical conjugation to biomolecules without the need to screen for a suitable methionine conjugation site. We demonstrate the versatility of this approach by producing a fluorescently labeled antibody, an antibody–drug conjugate, and a small molecule-conjugated oligonucleotide. We anticipate that BioReACT will be useful to rapidly introduce biorthogonal handles into biomolecules using biotin, a functional group that is widespread and straightforward to install.

中文翻译：

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生物素作为一种反应性处理剂，可选择性地标记蛋白质和 DNA 的小分子

生物素是与蛋白质和 DNA 生物偶联的常见功能手柄，但其用途仅限于含蛋白质的偶联配偶体，例如链霉亲和素及其衍生物。最近，开发了氧氮丙啶试剂，可选择性地将蛋氨酸的硫醚偶联到蛋白质表面，这种方法称为氧化还原激活化学标记 (ReACT)。这些试剂生成的硫酰亚胺键的稳定性取决于溶剂的可及性和 oxaziridine 上的取代。在这里，我们表明氧氮丙啶试剂与生物素中的硫醚快速反应，生成在 37 °C 下可稳定超过 10 天的亚硫酰亚胺产物。这种方法，我们称之为生物素氧化还原激活化学标记 (BioReACT)，扩展了生物素标记的实用性，并实现了与生物分子的可预测和稳定的化学缀合，而无需筛选合适的甲硫氨酸缀合位点。我们通过生产荧光标记抗体、抗体-药物偶联物和小分子偶联寡核苷酸证明了这种方法的多功能性。我们预计 BioReACT 将有助于使用生物素将双正交手柄快速引入生物分子，生物素是一种广泛存在且易于安装的官能团。