Transfer-messenger RNA

tmRNA combines features of tRNA and mRNA.

Secondary structure of E. coli tmRNA. Shown are the 5' and 3' ends of the 363-nucleotide RNA chain numbered in increments of ten. Short lines indicate Watson-Crick pairings (G-C and A-U); dots are G-U pairings. Prominent are the tRNA-like domain (TLD), the messenger RNA-like region (MLR), and the four pseudoknots (pk1 to pk4). The MLR encodes the tag peptide between resume and stop codons. RNA helices (numbered one to 12) and their sections (letters) are gray.

Cartoon ribbon structure of the tRNA-like domain of tmRNA. The domain consists of the 3' and 5' ends of the tmRNA. Image was created using Pymol molecular imaging software for students and data obtained from the RCSB Protein Data Bank file for structure 1J1H[17]

Cartoon ribbon structure of the tmRNA dedicated binding protein, SmpB. Image was created using Pymol molecular imaging software for students and data obtained from the RCSB Protein Data Bank file for structure 1CZJ[18]

Transfer-messenger RNA (abbreviated tmRNA, also known as 10Sa RNA and by its genetic name SsrA) is a bacterial RNA molecule with dual tRNA-like and messenger RNA-like properties. The tmRNA forms a ribonucleoprotein complex (tmRNP) together with Small Protein B (SmpB), Elongation Factor Tu (EF-Tu), and ribosomal protein S1. In trans-translation, tmRNA and its associated proteins bind to bacterial ribosomes which have stalled in the middle of protein biosynthesis, for example when reaching the end of a messenger RNA which has lost its stop codon. The tmRNA is remarkably versatile: it recycles the stalled ribosome, adds a proteolysis-inducing tag to the unfinished polypeptide, and facilitates the degradation of the aberrant messenger RNA. In the majority of bacteria these functions are carried out by standard one-piece tmRNAs. In other bacterial species, a permuted ssrA gene produces a two-piece tmRNA in which two separate RNA chains are joined by base-pairing.

单词	TmRNA
释义	TmRNA 英语百科 Transfer-messenger RNA Transfer-messenger RNA (abbreviated tmRNA, also known as 10Sa RNA and by its genetic name SsrA) is a bacterial RNA molecule with dual tRNA-like and messenger RNA-like properties. The tmRNA forms a ribonucleoprotein complex (tmRNP) together with Small Protein B (SmpB), Elongation Factor Tu (EF-Tu), and ribosomal protein S1. In trans-translation, tmRNA and its associated proteins bind to bacterial ribosomes which have stalled in the middle of protein biosynthesis, for example when reaching the end of a messenger RNA which has lost its stop codon. The tmRNA is remarkably versatile: it recycles the stalled ribosome, adds a proteolysis-inducing tag to the unfinished polypeptide, and facilitates the degradation of the aberrant messenger RNA. In the majority of bacteria these functions are carried out by standard one-piece tmRNAs. In other bacterial species, a permuted ssrA gene produces a two-piece tmRNA in which two separate RNA chains are joined by base-pairing.
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TmRNA

Transfer-messenger RNA