Figure 5.  A comparison of the structures of HIV-1 RT from complexes with five different NNRTIs.  The alpha-carbon backbones of the five HIV-1 RTs are shown as colored ribbons (the key is given in the figure).  To simplify the comparisons of the protein structures, the NNRTIs are not shown.  The subdomains of the p66 subunit (in particular, the fingers and thumb) can move relative to the core of the enzyme; however, the extent of the movement among the five NNRTI-containing structures is much smaller than the movements that are seen when the structure of an NNRTI-bound RT is compared to the structure of unliganded RT or to the structures of RTs that have a bound nucleic acid (see Figure 6).  The superposition was performed using the program ALIGN.  To look at the structure comparison in more detail, the PDB file for the comparison of the five structures can be downloaded here (NNRTI.pdb).