A novel open-barrel structure of octameric translin reveals a potential RNA entryway

J Mol Biol. 2015 Feb 27;427(4):756-762. doi: 10.1016/j.jmb.2014.11.013. Epub 2014 Nov 26.

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.

Keywords: RNA; TRAX; octamer; open barrel; translin.

MeSH terms

  • Animals
  • Binding Sites
  • Chromatography, Gel
  • Crystallography, X-Ray
  • DNA, Single-Stranded / chemistry*
  • DNA, Single-Stranded / ultrastructure
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / ultrastructure
  • Humans
  • Mice
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA-Binding Proteins / chemistry*
  • RNA-Binding Proteins / ultrastructure
  • X-Ray Diffraction

Substances

  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • RNA-Binding Proteins
  • TSN protein, human