Figure 1.

General labeling scheme for addition of fluorophores to the DNA. (A) 2-Step, mTAG conjugation of fluorophores to DNA. In the first step a reactive moiety is transferred to the DNA by DNA MTases, in a subsequent reaction the dye is coupled to the DNA. (B) One-pot labeling of DNA. An NHS-ester derivative (e.g. fluorophore) is coupled directly to the AdoMet analogue, this mixture is then incubated with methyltransferase and DNA. Hence, a fluorescent moiety is directly transferred to the DNA by the methyltransferase enzyme.