Different sensitivity of H69 modification enzymes RluD and RlmH to mutations in Escherichia coli 23S rRNA

详细信息	查看全文 | 推荐本文 |

• 作者：Margus Leppik¹ ; Rya Ero¹ ; Aivar Liiv ; Kalle Kipper ; Jaanus Remme ; ^{jremme@ebc.ee}
• 关键词：Stem-loop 69 ; 23S rRNA ; RluD ; RlmH ; Pseudouridine ; Methylation
• 刊名：Biochimie
• 出版年：2012
• 期刊代码：24_03009084
• 类别：bio
• 出版时间：May, 2012
• 卷：94
• 期：5
• 页码：1080-1089
• 文件大小：720 K

摘要

Nucleoside modifications are introduced into the ribosomal RNA during the assembly of the ribosome. The number and the localization of the modified nucleosides in rRNAs are known for several organisms. In bacteria, rRNA modified nucleosides are synthesized by a set of specific enzymes, the majority of which have been identified in Escherichia coli. Each rRNA modification enzyme recognizes its substrate nucleoside(s) at a specific stage of ribosome assembly. Not much is known about the specificity determinants involved in the substrate recognition of the modification enzymes. In order to shed light on the substrate specificity of RluD and RlmH, the enzymes responsible for the introduction of modifications into the stem-loop 69 (H69), we monitored the formation of H69 pseudouridines (唯) and methylated pseudouridine (m³唯) in聽vitro on ribosomes with alterations in 23S rRNA. While the synthesis of 唯s in H69 by RluD is relatively insensitive to the point mutations at neighboring positions, methylation of one of the 唯s by RlmH exhibited a much stronger sensitivity. Apparently, in spite of synthesizing modifications in the same region or even at the same position of rRNA, the two enzymes employ different substrate recognition mechanisms.