Figure 5.

Sites of intron integration in the 23S rRNA. (A) Reaction sites in domains II, IV, and V. Solid circle, 3′ junctions; open circle, 5′ junction. Position 1926 in domain IV is indicated. Secondary structure is from ref. 32. (B) Alignment of target sequences. Numbers on the left give the position preceding the intron insertion, and sequences on the right are complementary to the IGS, shown at the top. Uppercase, experimentally determined sequence; lowercase, inferred from 23S sequence; boldface, nucleotide 5′ of the integration site.