Nematode mitochondria possess extremely truncated tRNAs. Of 22 tRNAs, 20 lack the entire T-arm. The T-arm is necessary for the binding of canonical tRNAs and EF (elongation factor)-Tu (thermo-unstable). The nematode mitochondrial translation system employs two different EF-Tu factors named EF-Tu1 and EF-Tu2. Our previous study showed that nematode Caenorhabditis elegans EF-Tu1 binds specifically to T-armless tRNA. C. elegans EF-Tu1 has a 57-amino acid C-terminal extension that is absent from canonical EF-Tu, and the T-arm-binding residues of canonical EF-Tu are not conserved. In this study, the recognition mechanism of T-armless tRNA by EF-Tu1 was investigated. Both modification interference assays and primer extension analysis of cross-linked ternary complexes revealed that EF-Tu1 interacts not only with the tRNA acceptor stem but also with the D-arm. This is the first example of an EF-Tu recognizing the D-arm of a tRNA. The binding activity of EF-Tu1 was impaired by deletion of only 14 residues from the C-terminus, indicating that the C-terminus of EF-Tu1 is required for its binding to T-armless tRNA. These results suggest that C. elegans EF-Tu1 recognizes the D-arm instead of the T-arm by a mechanism involving its C-terminal region. This study sheds light on the co-evolution of RNA and RNA-binding proteins in nematode mitochondria.
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Research Article|
September 27 2006
A protein extension to shorten RNA: elongated elongation factor-Tu recognizes the D-arm of T-armless tRNAs in nematode mitochondria
Masayuki Sakurai;
Masayuki Sakurai
*Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
†Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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Yoh-ichi Watanabe;
Yoh-ichi Watanabe
‡Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Kimitsuna Watanabe;
Kimitsuna Watanabe
1
*Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
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Takashi Ohtsuki
Takashi Ohtsuki
2
*Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
2To whom correspondence should be addressed (email ohtsuk@cc.okayama-u.ac.jp). Present address: Department of Bioscience and Biotechnology, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
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Publisher: Portland Press Ltd
Received:
May 26 2006
Revision Received:
July 11 2006
Accepted:
July 21 2006
Accepted Manuscript online:
July 21 2006
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London
2006
Biochem J (2006) 399 (2): 249–256.
Article history
Received:
May 26 2006
Revision Received:
July 11 2006
Accepted:
July 21 2006
Accepted Manuscript online:
July 21 2006
Connected Content
A commentary has been published:
Intricacies and surprises of nuclear–mitochondrial co-evolution
Citation
Masayuki Sakurai, Yoh-ichi Watanabe, Kimitsuna Watanabe, Takashi Ohtsuki; A protein extension to shorten RNA: elongated elongation factor-Tu recognizes the D-arm of T-armless tRNAs in nematode mitochondria. Biochem J 15 October 2006; 399 (2): 249–256. doi: https://doi.org/10.1042/BJ20060781
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