tmRNA-mediated trans-translation as the major ribosome rescue system in a bacterial cell.
tmRNA-mediated trans-translation as the major ribosome rescue system in a bacterial cell.
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DOI：
10.3389/fgene.2014.00066
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发表时间：
2014
影响因子：
3.7
通讯作者：
Muto A
中科院分区：
文献类型：
--
作者：
Himeno H;Kurita D;Muto A
转移信使RNA（transfer messenger RNA，tmRNA;也称为10 Sa RNA或SsrA RNA）是一种在细菌中保守的小RNA分子。它与tRNA具有结构和功能相似性：它具有tRNA样结构的上半部分，其5'端由RNase P加工，它具有典型的tRNA特异性碱基修饰，它被丙氨酸氨酰化，它在氨酰化后与EF-Tu结合，它与EF-Tu和GTP一起进入核糖体。然而，tmRNA缺乏反密码子，取而代之的是它有一个称为标签肽的短肽的编码序列。在tRNA结合蛋白SmpB的帮助下，tmRNA作为tRNA和mRNA的作用的精心相互作用促进了反式翻译，其从两个mRNA分子产生单个多肽。最初，丙氨酰-tmRNA与EF-Tu和SmpB复合进入停滞的核糖体的空A位点，如氨酰-tRNA，但没有密码子-反密码子相互作用，随后截短的mRNA被tmRNA的标签编码区取代。在这些过程中，不仅tmRNA而且SmpB在结构和功能上模拟tRNA和mRNA。因此，反式翻译拯救了停滞的核糖体，从而允许核糖体的再循环。由于标签肽作为AAA+蛋白酶的靶标，反式翻译产物优先降解，因此它们不会在细胞中积累。虽然最近已经发现了替代的救援系统，但反式翻译是唯一普遍存在于细菌中的系统。此外，它的独特之处在于它采用了小RNA，并且它防止了细胞中截短mRNA的非功能性蛋白质的积累。它可能在挽救细菌细胞中停滞的翻译中发挥主要作用。
Transfer messenger RNA (tmRNA; also known as 10Sa RNA or SsrA RNA) is a small RNA molecule that is conserved among bacteria. It has structural and functional similarities to tRNA: it has an upper half of the tRNA-like structure, its 5’ end is processed by RNase P, it has typical tRNA-specific base modifications, it is aminoacylated with alanine, it binds to EF-Tu after aminoacylation and it enters the ribosome with EF-Tu and GTP. However, tmRNA lacks an anticodon, and instead it has a coding sequence for a short peptide called tag-peptide. An elaborate interplay of actions of tmRNA as both tRNA and mRNA with the help of a tmRNA-binding protein, SmpB, facilitates trans-translation, which produces a single polypeptide from two mRNA molecules. Initially alanyl-tmRNA in complex with EF-Tu and SmpB enters the vacant A-site of the stalled ribosome like aminoacyl-tRNA but without a codon–anticodon interaction, and subsequently truncated mRNA is replaced with the tag-encoding region of tmRNA. During these processes, not only tmRNA but also SmpB structurally and functionally mimics both tRNA and mRNA. Thus trans-translation rescues the stalled ribosome, thereby allowing recycling of the ribosome. Since the tag-peptide serves as a target of AAA+ proteases, the trans-translation products are preferentially degraded so that they do not accumulate in the cell. Although alternative rescue systems have recently been revealed, trans-translation is the only system that universally exists in bacteria. Furthermore, it is unique in that it employs a small RNA and that it prevents accumulation of non-functional proteins from truncated mRNA in the cell. It might play the major role in rescuing the stalled translation in the bacterial cell.
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影响因子：
3
作者：
Cheng, Kimberley;Ivanova, Natalia;Lindahl, Martin
通讯作者：
Lindahl, Martin
影响因子：
16
作者：
Chiba, Shinobu;Ito, Koreaki
通讯作者：
Ito, Koreaki
DOI：
10.1073/pnas.012602299
发表时间：
2002-01-22
影响因子：
11.1
作者：
Akerley, BJ;Rubin, EJ;Mekalanos, JJ
通讯作者：
Mekalanos, JJ
影响因子：
3.6
作者：
Abe, Teppei;Sakaki, Kazutaka;Muto, Akira
通讯作者：
Muto, Akira
影响因子：
11.4
作者：
Felden, B;Hanawa, K;Crain, PF
通讯作者：
Crain, PF