FIGURE 2.

Comparison of the closure of the central cyclic 40-mer and 42-mer strands in DAE molecules. This is a denaturing gel autoradiogram that compares ligation efficiencies for two possible species of DAE molecules. Lane 1 contains linear markers (labeled No. L, where No. represents their lengths) and lanes 8 and 9 contain cyclic markers (labeled No. C, where No. again represents their lengths). Lanes 2–4 contain bands derived from the labeled 40-mer, and lanes 5–7 contain bands derived from the labeled 42-mer. Lanes 2 and 5 contain unligated material, lanes 3 and 6 contain the ligation products of these strands in the DAE context, and lanes 4 and 7 contain the results of treating the material in lanes 3 and 6, respectively, with exonuclease III. It is evident that under the conditions used, the 40-mer cyclizes only partially, whereas the 42-mer cyclizes almost completely.