FIG 4.

Organizations of the major groups of transposons of the IS605 superfamily. Transposition of nonautonomous transposons encoding IscB and TnpB is predicted to be catalyzed by the Y1 tyrosine transposase encoded by autonomous transposons IS200, IS605, and ISC2Y. The Y1 transposase binds to the transposon termini, which contain imperfect hairpins formed by the subterminal inverted repeats (green and red arrows). Short nonautonomous TEs transposed by the IS605-like Y1 transposase that do not encode any proteins are known as PATEs and REPs. Four types of specific 4-bp target sites are listed for transposons from different groups in the 4 columns on the right. In the target site sequences, the vertical lines indicate the exact positions of transposon insertion. Previously reported target sites and the transposon insertion positions are shown in the last column. The dashed box denotes new types of target sites described in this work.