To respond and adapt to environmental challenges, prokaryotes regulate cellular processes rapidly and reversibly through protein phosphorylation and dephosphorylation. This study investigates the intracellular proteome and Ser/Thr/Tyr phosphoproteome of the oral commensal Streptococcus gordonii. Intracellular proteins from planktonic cells of S. gordonii DL1 were extracted and subjected to 2D-gel electrophoresis. Proteins in general were visualized using Coomassie Brilliant Blue and T-Rex staining. Phosphorylated proteins were visualized with Pro-Q Diamond Phosphoprotein Gel Stain. Proteins were identified by LC-MS/MS and sequence analysis. In total, sixty-one intracellular proteins were identified in S. gordonii DL1, many of which occurred at multiple isoelectric points. Nineteen of these proteins were present as one or more Ser/Thr/Tyr phosphorylated form. The identified phosphoproteins turned out to be involved in a variety of cellular processes. Nineteen phosphoproteins involved in various cellular functions were identified in S. gordonii. This is the first time the global intracellular Ser/Thr/Tyr phosphorylation profile has been analysed in an oral streptococcus. Comparison with phosphoproteomes of other species from previous studies showed many similarities. Proteins that are consistently found in a phosphorylated state across several species and growth conditions may represent a core phosphoproteome profile shared by many bacteria.

中文翻译：

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口腔共生 Streptococcus gordonii DL1 的细胞内 Ser/Thr/Tyr 磷酸蛋白质组。

为了应对和适应环境挑战，原核生物通过蛋白质磷酸化和去磷酸化快速可逆地调节细胞过程。本研究调查了口腔共生 Streptococcus gordonii 的细胞内蛋白质组和 Ser/Thr/Tyr 磷酸蛋白质组。从 S. gordonii DL1 的浮游细胞中提取细胞内蛋白质并进行二维凝胶电泳。使用考马斯亮蓝和 T-Rex 染色通常可以使蛋白质可视化。用 Pro-Q Diamond Phosphoprotein Gel Stain 观察磷酸化蛋白质。通过LC-MS/MS和序列分析鉴定蛋白质。总共在 S. gordonii DL1 中鉴定了 61 种细胞内蛋白质，其中许多发生在多个等电点。这些蛋白质中有 19 种以一种或多种 Ser/Thr/Tyr 磷酸化形式存在。结果证明，鉴定出的磷蛋白参与了多种细胞过程。在 S. gordonii 中鉴定了 19 种参与各种细胞功能的磷蛋白。这是首次在口腔链球菌中分析全局细胞内 Ser/Thr/Tyr 磷酸化谱。与之前研究中其他物种的磷酸化蛋白质组的比较显示出许多相似之处。在多个物种和生长条件下始终以磷酸化状态发现的蛋白质可能代表了许多细菌共有的核心磷酸化蛋白质组谱。在 S. gordonii 中鉴定了 19 种参与各种细胞功能的磷蛋白。这是首次在口腔链球菌中分析全局细胞内 Ser/Thr/Tyr 磷酸化谱。与之前研究中其他物种的磷酸化蛋白质组的比较显示出许多相似之处。在多个物种和生长条件下始终以磷酸化状态发现的蛋白质可能代表了许多细菌共有的核心磷酸化蛋白质组谱。在 S. gordonii 中鉴定了 19 种参与各种细胞功能的磷蛋白。这是首次在口腔链球菌中分析全局细胞内 Ser/Thr/Tyr 磷酸化谱。与之前研究中其他物种的磷酸化蛋白质组的比较显示出许多相似之处。在多个物种和生长条件下始终以磷酸化状态发现的蛋白质可能代表了许多细菌共有的核心磷酸化蛋白质组谱。