Enzymatic conversion of adenosine to inosine and to N-1-methylinosine in transfer RNAs: A review

被引：90

作者：

Grosjean, H ^{[1
]}

Auxilien, S ^{[1
]}

Constantinesco, F ^{[1
]}

Simon, C ^{[1
]}

Corda, Y ^{[1
]}

Becker, HF ^{[1
]}

Foiret, D ^{[1
]}

Morin, A ^{[1
]}

Jin, YX ^{[1
]}

Fournier, M ^{[1
]}

Fourrey, JL ^{[1
]}

机构：

[1] INST CHIM SUBST NAT, F-91198 GIF SUR YVETTE, FRANCE

来源：

BIOCHIMIE | 1996年 / 78卷 / 06期

关键词：

RNA; inosine; methylation; editing; deaminase; methyltransferase; autoantibodies; polymyositis;

D O I：

10.1016/0300-9084(96)84755-9

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Inosine (6-deaminated adenosine) is a characteristic modified nucleoside that is found at the first anticodon position (position 34) of several tRNAs of eukaryotic and eubacterial origins, while N-1-methylinosine is found exclusively at position 37 (3' adjacent to the anticodon) of eukaryotic tRNA(Ala) and at position 57 (in the middle of the Psi loop) of several tRNAs from halophilic and thermophilic archaebacteria. Inosine has also been recently found in double-stranded RNA, mRNA and viral RNAs. As for all other modified nucleosides in RNAs, formation of inosine and inosine derivative in these RNA is catalysed by specific enzymes acting after transcription of the RNA genes. Using recombinant tRNAs and T gamma-runoff transcripts of several tRNA genes as substrates, we have studied the mechanism and specificity of tRNA-inosine-forming enzymes. The results show that inosine-34 and inosine-37 in tRNAs are both synthesised by a hydrolytic deamination-type reaction, catalysed by distinct tRNA:adenosine deaminases. Recognition of tRNA substrates by the deaminases does not strictly depend on a particular 'identity' nucleotide. However, the efficiency of adenosine to inosine conversion depends on the nucleotides composition of the anticodon loop and the proximal stem as well as on 3D-architecture of the tRNA. In eukaryotic tRNA(Ala), N-1-methylinosine-37 is formed from inosine-37 by a specific SAM-dependent methylase, while in the case of N-1-methylinosine-57 in archaeal tRNAs, methylation of adenosine-57 into N-1-methyladenosine-57 occurs before the deamination process The T Psi-branch of fragmented tRNA is the minimalist substrate for the N-1-methylinosine-57 forming enzymes. Inosine-34 and N-1-methylinosine-37 in human tRNA(Ala) are targets for specific autoantibodies which are present in the serum of patients with inflammatory muscle disease of the PL-12 polymyositis type. Here we discuss the mechanism, specificity and general properties of the recently discovered RNA:adenosine deaminases/editases acting on double-stranded RNA, intron-containing mRNA and viral RNA in relation to those of the deaminases acting on tRNAs.

引用

页码：488 / 501

页数：14

共 101 条

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