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Function of the SmpB Tail in Transfer-messenger RNA Translation Revealed by a Nucleus-encoded Form
- Source :
- Journal of Biological Chemistry. 280:5503-5509
- Publication Year :
- 2005
- Publisher :
- Elsevier BV, 2005.
-
Abstract
- Stalled bacterial ribosomes are freed when they switch to the translation of transfer-messenger RNA (tmRNA). This process requires the tmRNA-binding and ribosome-binding cofactor SmpB, a beta-barrel protein with a protruding C-terminal tail of unresolved structure. Some plastid genomes encode tmRNA, but smpB genes have only been reported from bacteria. Here we identify smpB in the nuclear genomes of both a diatom and a red alga encoding a signal for import into the plastid, where mature SmpB could activate tmRNA. Diatom SmpB was active for tmRNA translation with bacterial components in vivo and in vitro, although less so than Escherichia coli SmpB. The tail-truncated diatom SmpB, the hypothetical product of a misspliced mRNA, was inactive in vivo. Tail-truncated E. coli SmpB was likewise inactive for tmRNA translation but was still able to bind ribosomes, and its affinity for tmRNA was only slightly diminished. This work suggests that SmpB is a universal cofactor of tmRNA. It also reveals a tail-dependent role for SmpB in tmRNA translation that supersedes a simple role of linking tmRNA to the ribosome, which the SmpB body alone could provide.
- Subjects :
- Molecular Sequence Data
Biology
Biochemistry
Ribosome
Escherichia coli
Aminoacylation
Amino Acid Sequence
Plastid
Molecular Biology
Gene
Alleles
Sequence Deletion
Cell Nucleus
Diatoms
Genetics
Messenger RNA
RNA-Binding Proteins
RNA
Translation (biology)
Cell Biology
Cell biology
RNA, Bacterial
Eukaryotic Cells
Protein Biosynthesis
Rhodophyta
Ribosomes
Trans-translation
Transfer-messenger RNA
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 280
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....eec3754a6642f35ee6c2f30ca17748ca