Ligating DNA with DNA

Cloning DNA typically involves the joining of target DNAs with vector constructs by enzymatic ligation. A commonly used enzyme for this reaction is bacteriophage T4 DNA ligase, which requires ATP as the energy source to catalyze the otherwise unfavorable formation of a phosphodiester bond. Using in vitro selection, we have isolated a DNA sequence that catalyzes the ligation of DNA in the absence of protein enzymes. We have used the action of …