Portal de Periódicos da CAPES

[12] Glu-tRNAGin: An intermediate in yeast mitochondrial protein synthesis

1984; Academic Press; Linguagem: Inglês

10.1016/0076-6879(84)06014-6

1557-7988

Nancy Martín, Murray Rabinowitz,

RNA Research and Splicing

This chapter deals with Glu-tRNAGln, which is an intermediate in yeast mitochondrial protein synthesis. The isoaccepting Glu-tRNAs are detected by charging isolated yeast mitochondrial tRNAs with [3H]glutamic acid using synthetase preparations obtained from mitochondria and fractionating the resulting aminoacyl- tRNA by RPC-5. Two distinct peaks of tRNA which accept glutamic acid are separated. Both fractions are isolated and shown to be gene products of mitochondrial DNA by nucleic acid hybridization. The hybridization of the two tRNAs to mitochondrial DNA indicates that the two tRNAs are coded by two different genes. Hybridization competition experiments and mapping experiments give further confirmation that these tRNAs are different in primary sequence. Subsequent experiments examine the codon responses of these two tRNAs in ribosome binding studies with synthetic oligonucleotides using the methods of Nirenberg and Leder. The tRNA eluting first from the RPC-5 column (GluI-tRNA) respond to oligonucleotides including the glutamic acid GAA and GAG codons. The tRNA eluting at higher salt (GluII-tRNA) did not bind to ribosomes in response to glutamic acid codons but did bind when an oligonucleotide including the glutamine codon CAA is used.