Fig. 1

RAL bound in the IN active site. Model showing raltegravir (RAL) bound in the active site of HIV-1 IN (see Hare et al. [9]). The bound form of RAL (green) chelates the Mg²⁺ ions at the active site through the diketo motif. The oxidazole ring and benzyl moiety of RAL interact, through π–π stacking, with Y143 (teal) and the penultimate cytosine (magenta) at the 3′ end of the viral DNA strand, respectively. Binding of RAL causes the adenosine (magenta) to move away from IN active site (side chains are white), which inhibits the strand transfer reaction. Residues that are mutated in resistant forms of IN are shown (side chains colored teal), and the letter designating the mutant amino acid is indicated in red