A bifunctional DNA binding region in Tn5 transposase.

Tn5 transposition is a complicated process that requires the formation of a highly ordered protein-DNA structure, a synaptic complex, to catalyse the movement of a sequence of DNA (transposon) into a target DNA. Much is known about the structure of the synaptic complex and the positioning of protein-DNA contacts, although many protein-DNA contacts remain largely unstudied. In particular, there is little evidence for the positioning of donor DNA and target DNA.

Tn5 synaptic complex formation: role of transposase residue W450.

A series of Tn5 transposases (Tnp's) with mutations at the conserved amino acid position W450, which was structurally predicted to be important for synapsis, have been generated and characterized. This study demonstrates that W450 is involved in hydrophobic (and possibly aromatic) contacts within the Tnp monomer that negatively regulate synaptic complex formation.