2gw6
NMR structure of the human tRNA endonuclease SEN15 subunit
Structural highlights
FunctionSEN15_HUMAN Non-catalytic subunit of the tRNA-splicing endonuclease complex, a complex responsible for identification and cleavage of the splice sites in pre-tRNA. It cleaves pre-tRNA at the 5' and 3' splice sites to release the intron. The products are an intron and two tRNA half-molecules bearing 2',3' cyclic phosphate and 5'-OH termini. There are no conserved sequences at the splice sites, but the intron is invariably located at the same site in the gene, placing the splice sites an invariant distance from the constant structural features of the tRNA body. The tRNA splicing endonuclease is also involved in mRNA processing via its association with pre-mRNA 3' end processing factors, establishing a link between pre-tRNA splicing and pre-mRNA 3' end formation, suggesting that the endonuclease subunits function in multiple RNA-processing events.[1] Publication Abstract from PubMedSplicing of eukaryal intron-containing tRNAs requires the action of the heterotetrameric splicing endonuclease, which is composed of two catalytic subunits, Sen34 and Sen2, and two structural subunits, Sen15 and Sen54. Here we report the solution structure of the human tRNA splicing endonuclease subunit HsSen15. To facilitate the structure determination, we removed the disordered 35 N-terminal and 14 C-terminal residues of the full-length protein to produce HsSen15(36-157). The structure of HsSen15(36-157), the first for a subunit of a eukaryal splicing endonuclease, revealed that the protein possesses a novel homodimeric fold. Each monomer consists of three alpha-helices and a mixed antiparallel/parallel beta-sheet, arranged in a topology similar to that of the C-terminal domain of Methanocaldococcus jannaschii endonuclease. The dimeric interface is dominated by a beta-barrel structure, formed by face-to-face packing of two, three-stranded beta-sheets. Each of the beta-sheets results from reciprocal parallel pairing of one beta-strand from one subunit with two other beta-strands from the symmetric subunit. The structural model provides insights into the functional assembly of the human tRNA splicing endonuclease. Three-dimensional structure determined for a subunit of human tRNA splicing endonuclease (Sen15) reveals a novel dimeric fold.,Song J, Markley JL J Mol Biol. 2007 Feb 9;366(1):155-64. Epub 2006 Nov 11. PMID:17166513[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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