The Transfer RNAs of Eukaryotic Organelles

Publisher Summary This chapter reviews that organelles contain a complete apparatus for the synthesis of proteins. It is clear that, at least in most cases, organelle tRNAs are transcripts of the organelle genome. The limited number of tRNAs present in organelles in contrast to prokaryotes and the eukaryotic cytoplasm-poses an interesting problem. The chapter discusses the two hypotheses: (1) That organelles evolved via endosymbiosis, and (2) that organelles evolved through invagination and compartmentalization of function. It suggests that either certain codons are not utilized by organelles or that, because of “wobble” at the third position of the anticodon, or a few isoacceptors-all 61 “sense” codons may be translated. As codon recognition by aminoacyl-tRNAs is determined, solely by the tRNA component, these elements of the protein synthetic machinery are in large part, responsible for maintaining the fidelity of the genetic code. The aim of this chapter is to review the development and progress of organelle tRNA research and the aminoacyl-tRNA synthetases.