Figure 1.

Transposition pathway and structure determination. a) Cartoon of transposition. The transposase (MuA) pairs the phage genome ends (blue and red). At each end, the same active site catalyzes the attack of H₂O at the phage-host junction and then the direct attack of the phage 3′-OH on target DNA (“strand transfer”). Target binding is nonspecific, and there is a 5 bp stagger between the sites of attack. Host and target DNAs may be entire circular replicons. After the ATP-dependent unfoldase ClpX disassembles the final strand transfer complex, the 3′ hydroxyls are used as replication primers, resulting in duplication of the phage genome. Our crystals contain the strand transfer product (3^rd panel). b) Domain structure of MuA. c) Experimental electron density map after phase improvement with Parrot superimposed on the model (contours are 1.2 and 2σ).

Note: part a was originally drawn in Illustrator, and an editable pdf can be supplied if needed. Part b was drawn in Word.