7-methylguanosine at the anticodon wobble position of squid mitochondrial tRNA(Ser)GCU: Molecular basis for assignment of AGA/AGG codons as serine in invertebrate mitochondria

Kozo Tomita, Takuya Ueda, Kimitsuna Watanabe

Research output: Contribution to journalArticle

35 Citations (Scopus)


In mitochondria of the squid, Loligo bleekeri, both the AGA and AGG codons are considered to correspond to serine instead of arginine as in the universal genetic code, and its genome encodes a single tRNA(Scr) gene with the anticodon GCT. Therefore, this gene product, tRNA(Ser)GCU, should be able to translate all four AGN (N; U, C, A, and G) codons as serine. To elucidate this recognition mechanism, the tRNA(Ser)GCU was isolated from squid liver and its complete nucleotide sequence determined. The tRNA(Ser)GCU was found to possess 7-methylguanosine (m7G) at the wobble position of the anticodon. This suggests that in the squid mitochondrial system, tRNA(Ser)GCU with the anticodon m7GCU can recognize not only the usual serine codons AGU and AGC, but also the unusual serine codons AGA and AGG, as in the case of starfish mitochondria (Matsuyama et al., J. Biol. Chem. 273 (1988) 3363-3368).

Original languageEnglish
Pages (from-to)78-82
Number of pages5
JournalBiochimica et Biophysica Acta - Gene Structure and Expression
Issue number1
Publication statusPublished - 1998 Jul 30
Externally publishedYes



  • (Squid, Loligo bleekeri)
  • 7- Methylguanosine
  • Decoding of AGA and AGG codons
  • Mitochondrion
  • TRNA(Ser)GCU

ASJC Scopus subject areas

  • Structural Biology
  • Biophysics
  • Biochemistry
  • Genetics

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