Figure 3.
This is a stereo pair.
Stereo close-up of interactions near the Mu DNA-target junction. Colors are the same as in Figure 2. A segment of DNA from a symmetry-related complex (yellow) binds the positively-charged domain IIIα of the R2-bound subunit (cyan). If the red Mu end DNA were extended to include flanking host DNA, it could lie where the yellow DNA does. The yellow sphere marks the phosphate group at the Mu-target DNA junction, and the main chains of the two active site D’s are also yellow (a third active site residue lies on a helix that could not be modeled). The loop that extends from domain IIα aa 410–430) to interact with the black target DNA is circled on the red subunit.