1J26

Solution structure of a putative peptidyl-tRNA hydrolase domain in a mouse hypothetical protein

1J26 の概要

• エントリーDOI: 10.2210/pdb1j26/pdb
• NMR情報: BMRB: 10121
• 分子名称: immature colon carcinoma transcript 1 (1 entity in total)
• 機能のキーワード: peptide chain release factors, rf-1, the ggq motif, immature colon carcinoma transcript 1, riken structural genomics/proteomics initiative, rsgi, structural genomics, translation
• 由来する生物種: Mus musculus (house mouse)
• 細胞内の位置: Mitochondrion (By similarity): Q8R035
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 12152.58

構造登録者

Nameki, N.,Kigawa, T.,Koshiba, S.,Kobayashi, N.,Tochio, N.,Inoue, M.,Yokoyama, S.,RIKEN Structural Genomics/Proteomics Initiative (RSGI) (登録日: 2002-12-25, 公開日: 2004-06-01, 最終更新日: 2023-12-27)

主引用文献

Handa, Y.,Hikawa, Y.,Tochio, N.,Kogure, H.,Inoue, M.,Koshiba, S.,Guntert, P.,Inoue, Y.,Kigawa, T.,Yokoyama, S.,Nameki, N.
Solution structure of the catalytic domain of the mitochondrial protein ICT1 that is essential for cell vitality
J.Mol.Biol., 2010

PubMed Abstract: The ICT1 protein was recently reported to be a component of the human mitoribosome and to have codon-independent peptidyl-tRNA hydrolysis activity via its conserved GGQ motif, although little is known about the detailed mechanism. Here, using NMR spectroscopy, we determined the solution structure of the catalytic domain of the mouse ICT1 protein that lacks an N-terminal mitochondrial targeting signal and an unstructured C-terminal basic-residue-rich extension, and we examined the effect of ICT1 knockdown (mediated by small interfering RNA) on mitochondria in HeLa cells using flow cytometry. The catalytic domain comprising residues 69-162 of the 206-residue full-length protein forms a structure with a β1-β2-α1-β3-α2 topology and a structural framework that resembles the structure of GGQ-containing domain 3 of class 1 release factors (RFs). Half of the structure, including the GGQ-containing loop, has essentially the same sequence and structure as those in RFs, consistent with the peptidyl-tRNA hydrolysis activity of ICT1 on the mitoribosome, which is analogous to RFs. However, the other half of the structure differs in shape from the corresponding part of RF domain 3 in that in ICT1, an α-helix (α1), instead of a β-turn, is inserted between strand β2 and strand β3. A characteristic groove formed between α1 and the three-stranded antiparallel β-sheet was identified as a putative ICT1-specific functional site by a structure-based alignment. In addition, the structured domain that recognizes stop codons in RFs is replaced in ICT1 by a C-terminal basic-residue-rich extension. It appears that these differences are linked to a specific function of ICT1 other than the translation termination mediated by RFs. Flow cytometry analysis showed that the knockdown of ICT1 results in apoptotic cell death with a decrease in mitochondrial membrane potential and mass. In addition, cytochrome c oxidase activity in ICT1 knockdown cells was decreased by 35% compared to that in control cells. These results indicate that ICT1 function is essential for cell vitality and mitochondrial function.

PubMed: 20869366
DOI: 10.1016/j.jmb.2010.09.033

実験手法

SOLUTION NMR