Sequence analysis of two yeast mitochondrial DNA fragments containing the genes for tRNA Ser UCR and tRNA Phe UUY.

Two restriction enzyme fragments containing yeast mitochondrial tRNA genes have been characterized by DNA sequence analysis. One of these fragments is 320 base pairs long and contains a tRNA Ser gene. The corresponding tRNA SER was isolated from yeast mitochondria and its nucleotide sequence also was determined. This mitochondrial tRNA is 90 nucleotides in length, has a G + C content of 38%, and has UGA as the anticodon. A portion of a 680-base-pair DNA fragment containing a tRNA Phe gene was also sequenced. The portion of this gene which codes for the mature tRNA is 75 base pairs in length, has a G + C content of 33%, and contains the anticodon GAA. Neither gene contains an intervening sequence or codes for the 3' CCA terminus. Both are surrounded by regions of more than 90% A + T. The significance of these sequences is discussed.