T-armless tRNAs and elongated elongation factor Tu.
Most tRNAs share a common secondary structure containing a T arm, a D arm, an anticodon arm and an acceptor stem. However, there are some exceptions. Most nematode mitochondrial tRNAs and some animal mitochondrial tRNAs lack the T arm, which is necessary for binding to canonical elongation factor Tu (EF-Tu). The mitochondria of the nematode Caenorhabditis elegans have a unique EF-Tu, named EF-Tu1, whose structure has supplied clues as to how truncated tRNAs can work in translation. EF-Tu1 has a C-terminal extension of about 60 aa that is absent in canonical EF-Tu. Recent data from our laboratory strongly suggests that EF-Tu1 recognizes the D-arm instead of the T arm by a mechanism involving this C-terminal region. Further biochemical analysis of mitochondrial tRNAs and EF-Tu from the distantly related nematode Trichinella spp. and sequence information on nuclear and mitochondrial DNA in arthropods suggest that T-armless tRNAs may have arisen as a result of duplication of the EF-Tu gene. These studies provide valuable insights into the co-evolution of RNA and RNA-binding proteins.
Ohtsuki
Takashi
T
Department of Bioscience and Biotechnology, Okayama University, Okayama, Japan. ohtsuk@cc.okayama-u.ac.jp
Watanabe
Yoh-ichi
Y
D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics*; D019143:Evolution, Molecular; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism
D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu