Equipment and reagent

  • T4 DNA Ligase
  • 10X ligation buffer (0.66m Tris-HCl,pH 7.6,50mM MgCl, 50mM DTT, 10mM ATP)
  • low temperature water-bath or heating-block
  • Gel electrophoresis apparatus


1. The volume of the ligation mixture and the DNA concentration depend on the type of ligation experiment.Use a 10μL reaction with DNA a concentration of > 100ng/μL to promote the formation of concatenamer ligation products,or a 10μL(or larger)reaction with DNA at a concentration < 10ng/μL to promote the formation of circular ligation product.

2.Add T4 DNA ligase.Check the supplier'documentation on enzyme activity,or more generally,add 0,25 U/μg of DNA for cohesive-end ligations,and 2,5U/μg of DNA for blunt-and ligations

3.Incubate the reaction mixture 3,5h at ambient temperature

4.Analyse for correct and complete ligation by gel electrophoresis using unligated material as a suitable control or also by transformation of E.coli cells if appropriate.