1.Excision reaction.

44.5 mM Tris–borate (pH 8.3)
7.5 mM Tris–HCl (pH 8.0)
1.15 mM EDTA
5 mM spermidine
60 mM KCl
0.275 mg/ml BSA
15% (v/v) glycerol.

Int 50~100 nM
IHF 35~70 nM
Xis 50~100 nM nM

incubate at 37 oC for 60 min

2. Integration reaction
50 nM Int
35 nM IHF

Reversible inhibitors of λ integrase-mediated recombination efficiently trap Holliday junction intermediates and form the basis of a novel assay for junction resolution. J. Biol. Chem. 2004;279:3472-3483.

Suicide recombination substrates yield covalent λ integrase-DNA complexes and lead to identification of the active site tyrosine. J. Biol. Chem. 1988;263:7678-7685.

http://nar.oxfordjournals.org/content/35/3/716.full#ref-33