Base methylations in the double-stranded RNA by a fused methyltransferase bearing unwinding activity

Satoshi Kimura, Yoshiho Ikeuchi, Kei Kitahara, Yuriko Sakaguchi, Takeo Suzuki, Tsutomu Suzuki

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Modifications of rRNAs are clustered in functional regions of the ribosome. In Helix 74 of Escherichia coli 23S rRNA, guanosines at positions 2069 and 2445 are modified to 7-methylguanosine(m7G) and N2- methylguanosine(m2G), respectively. We searched for the gene responsible for m7G2069 formation, and identified rlmL, which encodes the methyltransferase for m2G2445, as responsible for the biogenesis of m7G2069. In vitro methylation of rRNA revealed that rlmL encodes a fused methyltransferase responsible for forming both m7G2069 and m2G2445. We renamed the gene rlmKL. The N-terminal RlmL activity for m2G2445 formation was significantly enhanced by the C-terminal RlmK. Moreover, RlmKL had an unwinding activity of Helix 74, facilitating cooperative methylations of m7G2069 and m2G2445 during biogenesis of 50S subunit. In fact, we observed that RlmKL was involved in the efficient assembly of 50S subunit in a mutant strain lacking an RNA helicase deaD.

Original languageEnglish
Pages (from-to)4071-4085
Number of pages15
JournalNucleic acids research
Volume40
Issue number9
DOIs
Publication statusPublished - May 2012
Externally publishedYes

ASJC Scopus subject areas

  • Genetics

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