Figure 2.

The effect of oligonucleotide length on affinity column retention. (a) The capture oligonucleotide was designed to be complementary to the 5′ end of the pool. Symbols are as in Figure 1. (b) Comparison of four different capture oligonucleotides. W1–W10 indicate fractions obtained after washing the column with one column volume of selection buffer. (c) Residual retention of the pool on the column. To determine the extent of elution with the 12mer and 15mer capture oligonucleotides the experiments described in (b) were repeated, except that denaturing buffer containing 7 M urea was used. Fractions are the same as in (b). (d) The sequences adopted for selection experiments. F indicates fluorescein, while Q indicates a pendant DABCYL.