title: Specific and reversible inhibition of the blunt end joining activity of the T4 DNA ligase.
abstract: Specific, complete and reversible inhibition of the joining of blunt ended DNA duplexes catalyzed by the T4 DNA ligase can be obtained by using ATP, the enzyme cofactor, at concentrations of 5 mM and higher. On cohesive DNA ends, 5 mM ATP, which completely inhibits blunt end ligation, brings about only a limited (8%) reduction in the level of joining obtainable under optimal ATP concentration (0,5 mM or lower). A similar but less drastic uncoupling of the two kinds of joining can be achieved at lower ATP concentration (2,5 mM) using 1 mM Mg++. The joining of DNA blunt ends can also be inhibited almost completely by 10 mM spermidine, without noticeable effect on the joining of cohesive termini.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D011088:DNA Ligases / Q000037:antagonists & inhibitors*; D004262:DNA Restriction Enzymes; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D010957:Plasmids; D011118:Polynucleotide Ligases / Q000037:antagonists & inhibitors*; D013095:Spermidine / Q000494:pharmacology; D013604:T-Phages / Q000201:enzymology*
chemical_list: D000255:Adenosine Triphosphate; D004262:DNA Restriction Enzymes; D011088:DNA Ligases; D011118:Polynucleotide Ligases; D008274:Magnesium; D013095:Spermidine