This domain occurs at the C-terminus of transposases including E. coli tnpA (Swiss:Q46731). TnpA encodes a transposase and an inhibitor protein, the inhibitor only differs from the transposase by the absence of the N-terminal 55 amino acids, which includes most of this domain [1]. This domain consists of alpha helices and turns, and functions as a DNA-binding domain [2].

1: The three-dimensional structure of a Tn5 transposase-related protein determined to 2.9-A resolution. Davies DR, Braam LM, Reznikoff WS, Rayment I; J Biol Chem 1999;274:11904-11913. PMID:10207011

2: Structure/function insights into Tn5 transposition. Steiniger-White M, Rayment I, Reznikoff WS; Curr Opin Struct Biol. 2004;14:50-57. PMID:15102449