The nucleotide sequence of a smallmetT tRNA operon fromPhotobacterium leiognathi

Using a labelled oligonucleotide probe corresponding to the P. leiognathi operon has no homologue in E. coli, the high degree anticodon loop insertion of the pseudo tRNA genes found in of similarity between it and part of the metl operon strongly Photobacterium phosphoreum (1), we have isolated a 4.8 kb suggest a common ancestry. EcoRUHindUl fragment from Photobacterium leiognathi. A 840 base pair sequence of this fragment shows the presence of a small tRNA operon containing (—10)+ ( — 35) promoter elements, REFERENCES tRNAm, tRNAleu (5'-UAG-3') and a putative terminator structure. Comparison of these sequences with the metT operon ' Giroux.s., Beaudet.J. and Cedergren,R. (1988) Proc. Natl. Acad. Sti. USA e r i , ^ l u e 2. NakajimarN., Ozeb,H. and Shimura.Y. (.98.) Cell 23, 239-249. sequence is completely conserved. On the other 3. pearson,w.R. and Lipman,D.J. (1988) pWc. Natl. Acad. Sti. USA 85, hand, the tRNA^" sequences are 88.4% identical. Although the 2444-2448.