Figure 3.

Representative pre-rRNA group II introns readily self-splice under near-physiological conditions. The reaction is performed in the buffer containing 40 mM NH₄-HEPES pH 7.5, 150 mM NH₄Cl and 10% PEG-8000 under various magnesium ion concentrations as indicated on top of the gel lanes. After incubation at 37°C for 1 h, the reaction is quenched and loaded onto the 5% polyacrylamide/ 8 M urea gel (as described in Materials and Methods). The splicing gels are shown for (A) H.c.LSU.I1 intron, (B) C.i.LSU.I1 intron and (C) C.i.SSU.I1 intron. The middle part of the gel is not shown as no bands are visible within that region.