Percent exchange of peptides in RT-EFV complex. (A) p66 and (B) p51 subunits. Gray and orange bars above sequence represent α-helices and β-strands, with noted secondary structure labeled. Secondary structure represents the consensus of 1FK9 and 1IKW supplemented by the program STRIDE. Colored arrows above sequence represent polymerase subdomains: (blue) fingers, (red) palm, (green), thumb, (orange) connection; and (magenta) RNase H domain. Colored bars below sequence from top to bottom give exchange at 5, 60, 900, 3000, and 7200 s. Contact residues: (bold and underlined) dimer interface, (blue) polymerase and RNase H primer grips, (green) polymerase active site, (tan) RNase H active site, and (red) efavirenz.