FIG. 3.

Alignment of tRNA_CCU^Arg gene sequences. Base-pairing in the acceptor stem (A), anticodon stem (Ac), D stem (D), and T stem (T), the intron insertion site (arrow), the anticodon sequence (underline), and the position used to restrict amplification to tRNA_YCU^Arg genes (double underline) are indicated. N, any of the four possible nucleotides. I+ and I−, intron plus and minus, respectively. At, A. tumefaciens; Ah, A. halopraeferens; Am, A. marginale; Bj, B. japonicum; Er, E. risticii; El, E. longus; Me, M. extorquens; Pd, P. denitrificans; Rs, R. sphaeroides; Rc, R. centenaria; Rr, R. rubrum. Except for At and Ah, the tRNA_CCU^Arg genes were amplified by PCR. Sequences of the introns (shown in Fig. 1) and primers are omitted. The shorter sequences for E. longus and R. sphaeroides denote the use of the longer primer, ARG-5′EXT.