Skip to main content
. Author manuscript; available in PMC: 2021 Nov 2.
Published in final edited form as: J Phys Chem B. 2018 Nov 7;122(49):11519–11534. doi: 10.1021/acs.jpcb.8b07405

Figure 9.

Figure 9.

Flexible DNA bending at the H1 site may facilitate assembly of the phage lambda integration complex. Proteins and DNA segments in the model are shown as smoothed surfaces. The “intasome” assembles on phage DNA (“attP”; gray), with 3 copies of IHF (green) bending the DNA such that the integrase tetramer (brown) can bridge multiple DNA sites. Transient flapping of the IHF-induced bend at the H1 site (center panel) allows insertion of the bacterial integration site DNA (“attB”; magenta) into the complex, which is then trapped by closure of the H1 bend. Note that in these images the H1 binding site is oriented such that the (missing) A-tract side is on the right, i.e. orientation of IHF relative to the DNA at the H1 site is flipped 180° from that shown in Figure 1.