A Protein Extension to Shorten Rna: Elongated Elongation Factor-tu Recognizes the D-arm of T-armless Trnas in Nematode Mitochondria.
From: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan.
The Biochemical journal
- Publish Date: Oct 2006
- ISSN: 1470-8728
- Volume: 399
- Issue: 2
- Pages: 249-56
- Medium: Internet
- Language: English
- Citation (JAMA): Sakurai Masayuki, Watanabe Yoh-ichi, Watanabe Kimitsuna, et al. A Protein Extension to Shorten Rna: Elongated Elongation Factor-tu Recognizes the D-arm of T-armless Trnas in Nematode Mitochondria.. Biochem. J. Oct 2006;399:249-56
Abstract
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.
Mesh Headings (Keywords): Amino Acid Sequence, Animals, Ascaris suum, Base Sequence, Binding Sites, Caenorhabditis elegans, Cross-Linking Reagents, Ethylnitrosourea, Mitochondria, Molecular Sequence Data, Mutant Proteins, Nucleic Acid Conformation, Peptide Elongation Factor Tu, RNA, Helminth, RNA, Transfer, Met, Sequence Alignment, Sequence Deletion
Check for Full Text / PubMed Unique Identifier (PMID): 16859488
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