Protein tyrosine O-sulfation is an essential post-translational modification required for effective biological processes such as hemostasis, inflammatory response, and visual phototransduction. Because of its unstable nature under mass spectrometry conditions and residing on low-abundance cell surface proteins, sulfated tyrosine (sulfotyrosine) residues are difficult to detect or analyze. Enrichment of sulfotyrosine-containing proteins (sulfoproteins) from complex biological samples are typically required before analysis. In this work, we seek to engineer the phosphotyrosine binding pocket of a Src Homology 2 (SH2) domain to act as an antisulfotyrosine antibody mimic. Using tailored selection schemes, several SH2 mutants are identified with high affinity and specificity to sulfotyrosine. Further molecular docking simulations highlight potential mechanisms supporting observed characteristics of these SH2 mutants. Utilities of the evolved SH2 mutants were demonstrated by the detection and enrichment of sulfoproteins.

中文翻译：

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高特异性识别磺基酪氨酸的小蛋白支架工程

蛋白酪氨酸O-硫酸化是有效生物过程（如止血、炎症反应和视觉光转导）所需的重要翻译后修饰。由于其在质谱条件下的不稳定性质和存在于低丰度细胞表面蛋白上，硫酸化酪氨酸 (sulfotyrosine) 残基难以检测或分析。在分析之前，通常需要从复杂的生物样品中富集含磺基酪氨酸的蛋白质（硫蛋白）。在这项工作中，我们寻求设计 Src 同源 2 (SH2) 结构域的磷酸酪氨酸结合口袋，以充当抗磺基酪氨酸抗体模拟物。使用量身定制的选择方案，鉴定出对磺基酪氨酸具有高亲和力和特异性的几种 SH2 突变体。进一步的分子对接模拟突出了支持这些 SH2 突变体观察到的特征的潜在机制。通过检测和富集硫蛋白证明了进化的 SH2 突变体的效用。