FIG. 3.

Diagram showing the M41L and T215Y mutations (colored green) transferred into the HIV-1 RT double-stranded DNA-dTTP complex (6). An ATP molecule (atom-colored thick bonds with carbon atoms in gray) capable of the pyrophosphorolysis reaction has also been modeled into the protein by overlapping the β and γ phosphates of the bound dTTP. The protein side chains in the vicinity are shown in orange, and the three polymerase active-site aspartates are shown in cyan. The two magenta spheres represent the bound magnesiums. Distances for the putative interaction between ATP and the side chain of Y215 and the distance of the closest approach of L41 to ATP are marked.