The reactivity profile of atomic oxygen [O(³P)] in the condensed phase has shown a preference for the thiol group of cysteines. In this work, water-soluble O(³P)-precursors were synthesized by adding aromatic burdens and water-soluble sulphonic acid groups to the core structure of dibenzothiophene-S-oxide (DBTO) to study O(³P) reactivity in cell lysates and live cells. The photodeoxygenation of these compounds was investigated using common intermediates, which revealed that an increase in aromatic burdens to the DBTO core structure decreases the total oxidation yield due to competitive photodeoxygenation mechanisms. These derivatives were then tested in cell lysates and live cells to profile changes in cysteine reactivity using the isoTOP-ABPP chemoproteomics platform. The results from this analysis indicated that O(³P) significantly affects cysteine reactivity in the cell. Additionally, O(³P) was found to oxidize cysteines within peptide sequences with leucine and serine conserved at the sites surrounding the oxidized cysteine. O(³P) was also found to least likely oxidize cysteines among membrane proteins.

中文翻译：

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使用全蛋白质组分析识别易被光活化原子氧前体氧化的半胱氨酸残基

凝聚相中原子氧 [O( ³ P)]的反应性曲线显示出对半胱氨酸的硫醇基团的偏好。在这项工作中，通过在二苯并噻吩-硫氧化物 (DBTO)的核心结构中加入芳香负载和水溶性磺酸基团，合成了水溶性 O( ³ P)-前体，以研究 O( ³P) 细胞裂解物和活细胞的反应性。使用常见的中间体研究了这些化合物的光脱氧，结果表明，由于竞争性光脱氧机制，DBTO 核心结构的芳烃负荷增加会降低总氧化产率。然后在细胞裂解物和活细胞中测试这些衍生物，以使用 isoTOP-ABPP 化学蛋白质组学平台描绘半胱氨酸反应性的变化。该分析的结果表明，O( ³ P) 显着影响细胞中的半胱氨酸反应性。此外，发现O( ³ P) 氧化肽序列内的半胱氨酸，在氧化半胱氨酸周围的位点保守亮氨酸和丝氨酸。○( ³还发现 P) 最不可能氧化膜蛋白中的半胱氨酸。