Figure 4.
Testing the effect of a protein roadblock on linear diffusion by AAG. a) The 72mer substrate is depicted with an EcoRI dimer (green) bound to the central recognition site, and with an AAG monomer (blue) bound to the abasic product from the first excision reaction. If AAG is able to bypass the tightly bound protein (dashed arrow), then processive excision of the second εA will be observed. b) Structure of the EcoRI•DNA complex (41) is from the pdb (1ERI). The surfaces of the two EcoRI monomers are shown in blue and green and the DNA is depicted as a cartoon with the backbone in orange and the central EcoRI recognition sequence in yellow. c) The structure of the complex of the catalytic domain of AAG bound to εA-DNA (42) is from the pdb (1F4R). Images were rendered with Pymol (http://www.pymol.org).