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Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation
Published on: February 12, 2022
A novel open-barrel structure of octameric translin reveals a potential RNA entryway
Elad Eliahoo1, Ailie Marx1, Haim Manor1
1Department of Biology, Technion-Israel Institute of Technology, Haifa 320003, Israel.
Abstract:
The single-stranded DNA (ssDNA)/RNA binding protein translin was suggested to be involved in chromosomal translocations, telomere metabolism, and mRNA transport and translation. Oligonucleotide binding surfaces map within a closed cavity of translin octameric barrels, raising the question as to how DNA/RNA gain access to this inner cavity, particularly given that, to date, none of the barrel structures reported hint to an entryway. Here, we argue against a mechanism by which translin octamers may "dissociate and reassemble" upon RNA binding and report a novel "open"-barrel structure of human translin revealing a feasible DNA/RNA entryway into the cavity. Additionally, we report that translin not only is confined to binding of ssDNA oligonucleotides, or single-stranded extensions of double-stranded DNA (dsDNA), but also can bind single-stranded sequences internally embedded in dsDNA molecules.
Insights
Translin protein binds single-stranded DNA and RNA. A novel open-barrel structure reveals how these molecules access the translin cavity, challenging previous models.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Translin is an ssDNA/RNA binding protein implicated in various cellular processes.
- The structure of translin octameric barrels suggested a closed cavity, posing a question about DNA/RNA access.
- Previous models proposed octamer dissociation for ligand binding, lacking structural evidence.
Purpose of the Study:
- To investigate the mechanism of DNA/RNA access to the translin binding cavity.
- To challenge the octamer dissociation model for translin-ligand interaction.
- To elucidate the structural basis for translin's nucleic acid binding.
Main Methods:
- Structural analysis of human translin.
- Biochemical assays to determine binding capabilities.
Main Results:
- A novel "open"-barrel structure of human translin was identified.
- This open structure provides a feasible entryway for DNA/RNA into the binding cavity.
- Translin binds not only ssDNA/RNA but also internal ss sequences within dsDNA molecules.
Conclusions:
- Translin octamers do not require dissociation and reassembly to bind RNA.
- The open-barrel structure facilitates direct access of nucleic acids to the translin cavity.
- Translin exhibits broader nucleic acid binding capabilities than previously understood, including internal ssDNA sequences.
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