rRNA modifications play crucial roles in fine-tuning the delicate balance between translation speed and accuracy, yet the underlying mechanisms remain elusive. Comparative analyses of the rRNA modifications in taxonomically distant bacteria could help define their general, as well as species-specific, roles. In this study, we identified a new methyltransferase, RlmQ, in Staphylococcus aureus responsible for the Gram-positive specific m⁷G2601, which is not modified in Escherichia coli (G2574). We also demonstrate the absence of methylation on C1989, equivalent to E. coli C1962, which is methylated at position 5 by the Gram-negative specific RlmI methyltransferase, a paralog of RlmQ. Both modifications (S. aureus m⁷G2601 and E. coli m⁵C1962) are situated within the same tRNA accommodation corridor, hinting at a potential shared function in translation. Inactivation of S. aureus rlmQ causes the loss of methylation at G2601 and significantly impacts growth, cytotoxicity, and biofilm formation. These findings unravel the intricate connections between rRNA modifications, translation, and virulence in pathogenic Gram-positive bacteria.

中文翻译：

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RlmQ：一种新发现的 rRNA 修饰酶，可桥接金黄色葡萄球菌的 RNA 修饰和毒力特征

rRNA 修饰在微调翻译速度和准确性之间的微妙平衡方面发挥着至关重要的作用，但其潜在机制仍然难以捉摸。对分类学上距离较远的细菌的 rRNA 修饰进行比较分析可以帮助确定它们的一般作用以及物种特异性作用。在这项研究中，我们在金黄色葡萄球菌中鉴定出一种新的甲基转移酶 RlmQ，负责革兰氏阳性特异性 m ⁷ G2601，该酶在大肠杆菌(G2574) 中未经过修饰。我们还证明了 C1989 上不存在甲基化，相当于大肠杆菌C1962，它在 5 位被革兰氏阴性特异性 RlmI 甲基转移酶（RlmQ 的旁系同源物）甲基化。两种修饰（金黄色葡萄球菌m ⁷ G2601 和大肠杆菌m ⁵ C1962）都位于同一 tRNA 调节走廊内，暗示翻译中潜在的共享功能。金黄色葡萄球菌 rlmQ失活会导致 G2601 甲基化丧失，并显着影响生长、细胞毒性和生物膜形成。这些发现揭示了致病性革兰氏阳性菌中 rRNA 修饰、翻译和毒力之间的复杂联系。