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Crystal Structure of Human Translin in Open Conformation
Structural highlights
FunctionTSN_HUMAN DNA-binding protein that specifically recognizes consensus sequences at the breakpoint junctions in chromosomal translocations, mostly involving immunoglobulin (Ig)/T-cell receptor gene segments. Seems to recognize single-stranded DNA ends generated by staggered breaks occurring at recombination hot spots.[1] [2] Exhibits both single-stranded and double-stranded endoribonuclease activity. May act as an activator of RNA-induced silencing complex (RISC) by facilitating endonucleolytic cleavage of the siRNA passenger strand.[3] [4] Publication Abstract from PubMedThe 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. A Novel Open-Barrel Structure of Octameric Translin Reveals a Potential RNA Entryway.,Eliahoo E, Marx A, Manor H, Alian A J Mol Biol. 2014 Nov 26. pii: S0022-2836(14)00609-3. doi:, 10.1016/j.jmb.2014.11.013. PMID:25433126[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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