Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
J Mol Biol. 2012 Jan 6;415(1):16-21. doi: 10.1016/j.jmb.2011.10.044. Epub 2011 Nov 4.
Ten methyltransferases and one pseudouridine synthase are required for complete modification of the small ribosomal subunit in Escherichia coli. Nine methyltransferases, as well as the pseudouridine synthase, are already known. Here, we identify RsmJ, the last unknown methyltransferase required for methylation of m(2)G1516 in 16S ribosomal RNA (rRNA), as the protein encoded by yhiQ. Reverse transcription primer extension analysis reveals that rRNA extracted from a yhiQ deletion strain is not methylated at G1516. Moreover, methylation is restored upon gene complementation. Also, purified recombinant YhiQ specifically methylates 30S subunits extracted from the deletion strain. The absence of the yhiQ gene leads to a cold-sensitive phenotype. Based on these data, we propose that the yhiQ gene be renamed rsmJ.
在大肠杆菌中，完成小核糖体亚基的完全修饰需要 10 种甲基转移酶和 1 种假尿嘧啶合酶。其中 9 种甲基转移酶以及假尿嘧啶合酶已经被发现。在这里，我们鉴定出 RsmJ 是编码 yhiQ 的蛋白，它是在 16S rRNA 中 m(2)G1516 甲基化所必需的最后一个未知甲基转移酶。反转录引物延伸分析表明，从 yhiQ 缺失菌株中提取的 rRNA 在 G1516 处未被甲基化。此外，基因互补可恢复甲基化。而且，纯化的重组 YhiQ 可特异性地甲基化从缺失菌株中提取的 30S 亚基。yhiQ 基因的缺失导致对冷敏感的表型。基于这些数据，我们建议将 yhiQ 基因重新命名为 rsmJ。
