Figure 5.

Characterization of the major site of SegB endonuclease located within the phage T2L tRNA^Asn gene. (A) Images of DNA sequencing gels of the upper and lower strands are presented. Lanes 1 and 2 contain labeled extended DNA products before and after incubation with SegB endonuclease, respectively. Lanes G, A, T and C contain DNA sequencing products obtained in the presence of the corresponding terminator that were treated or not with endonuclease SegB as indicated. (B) DNA sequences surrounding the SegB cleavage site are shown. The cleavage points in the upper and lower strands are shown with closed and open arrowheads, respectively, and the major cleavage points are circled. The minimal sequence required for SegB endonuclease cleavage, which was deduced from the analysis presented in (A), is in capital letters.