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论文题目: Identification of determinants for tRNA substrate recognition by Escherichia coli C/U34 2 '-O-methyltransferase
英文论文题目: Identification of determinants for tRNA substrate recognition by Escherichia coli C/U34 2 '-O-methyltransferase
第一作者: Zhou, M; Long, T; Fang, ZP; Zhou, XL; Liu, RJ; Wang, ED
英文第一作者: Zhou, M; Long, T; Fang, ZP; Zhou, XL; Liu, RJ; Wang, ED
联系作者: Liu, RJ (reprint author), Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Biochem & Cell Biol, State Key Lab Mol Biol, Shanghai, Peoples R China.
英文联系作者: Liu, RJ (reprint author), Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Biochem & Cell Biol, State Key Lab Mol Biol, Shanghai, Peoples R China.
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发表年度: 2015
卷: 12
期: 8
页码: 900-911
摘要: Post-transcriptional modifications bring chemical diversity to tRNAs, especially at positions 34 and 37 of the anticodon stem-loop (ASL). TrmL is the prokaryotic methyltransferase that catalyzes the transfer of the methyl group from S-adenosyl-L-methionine to the wobble base of tRNA(CAA)(Leu) and tRNA(UAA)(Leu) isoacceptors. This Cm34/Um34 modification affects codon-anticodon interactions and is essential for translational fidelity. TrmL-catalyzed 2-O-methylation requires its homodimerization; however, understanding of the tRNA recognition mechanism by TrmL remains elusive. In the current study, by measuring tRNA methylation by TrmL and performing kinetic analysis of tRNA mutants, we found that TrmL exhibits a fine-tuned tRNA substrate recognition mechanism. Anticodon stem-loop minihelices with an extension of 2 base pairs are the minimal substrate for EcTrmL methylation. A35 is a key residue for TrmL recognition, while A36-A37-A38 are important either via direct interaction with TrmL or due to the necessity for prior isopentenylation (i(6)) at A37. In addition, TrmL only methylates pyrimidines but not purine residues at the wobble position, and the 2-O-methylation relies on prior N-6-isopentenyladenosine modification at position 37.
英文摘要: Post-transcriptional modifications bring chemical diversity to tRNAs, especially at positions 34 and 37 of the anticodon stem-loop (ASL). TrmL is the prokaryotic methyltransferase that catalyzes the transfer of the methyl group from S-adenosyl-L-methionine to the wobble base of tRNA(CAA)(Leu) and tRNA(UAA)(Leu) isoacceptors. This Cm34/Um34 modification affects codon-anticodon interactions and is essential for translational fidelity. TrmL-catalyzed 2-O-methylation requires its homodimerization; however, understanding of the tRNA recognition mechanism by TrmL remains elusive. In the current study, by measuring tRNA methylation by TrmL and performing kinetic analysis of tRNA mutants, we found that TrmL exhibits a fine-tuned tRNA substrate recognition mechanism. Anticodon stem-loop minihelices with an extension of 2 base pairs are the minimal substrate for EcTrmL methylation. A35 is a key residue for TrmL recognition, while A36-A37-A38 are important either via direct interaction with TrmL or due to the necessity for prior isopentenylation (i(6)) at A37. In addition, TrmL only methylates pyrimidines but not purine residues at the wobble position, and the 2-O-methylation relies on prior N-6-isopentenyladenosine modification at position 37.
刊物名称: RNA BIOLOGY
英文刊物名称: RNA BIOLOGY
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学科: Biochemistry & Molecular Biology
英文学科: Biochemistry & Molecular Biology
影响因子: 4.974
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论文类别: Article
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