Site-specific recombination and topoisomerization by Tn21 resolvase: role of metal ions.

The resolvase from the transposon Tn21 catalyses site-specific recombination between the two res sites on its DNA substrate both in the absence and presence of Mg2+ ions. This contrasts with reports on the resolvase from gamma-delta (Tn1000) and on other recombinational proteins that are homologous to Tn21 resolvase but which need Mg2+ for their activity… (More)