Figure 2.

Enhancement of T4 DNA ligase activity by supplemental oligonucleotides. (a) Unsuccessful 4-bp duplex reactions could be salvaged by utilizing a supplementary oligonucleotide, designed to complement the first oligonucleotide-dsDNA duplex but is unphosphorylated to prevent ligation of itself. Two hour ligation of the 4-bp reaction at 16°C supplemented with 3.33 μM of the hexamer, shows successful ligation (■) while reactions without the supplementary hexamer show no activity (◆). (b) Ligation reaction of an octamer supplemented with a second octamer in which one is used for ligation and the other is used to extend the duplex. A two hour ligation at 16°C of serial concentrations of the octamer with 3.33 μM of the supplementary octamer shows significant ligation (■) compared to reactions without the supplemental octamer (◆). (c) Unsuccessful 3-bp duplex reactions could be salvaged by utilizing a supplementary hexamer that hybridized at all six positions. A two hour ligation of the 3-bp reaction at 16°C with 3.33 μM supplementary hexamer shows successful ligation (■) while reactions without the supplementary hexamer show no activity (◆). (d) Ligation using a hexamer pair at 4°C for 16 hours shows limited improvement (■) compared to the unsupplemented (◆) control.