Effect of RT inhibitors on the activities of HIV-1, L1 and Ty1 RTs. The reverse transcriptase activities of HIV-1 RT (blue diamond), L1 RT (red square) and Ty1 RT (green triangle) were measured as described in the materials and methods. The RT activity of control assay without inhibitors was considered as 1.0. The activity in the presence of inhibitors was indicated as relative activity with respect to the control. All experiments were done at least three times and standard deviations are shown. (A) AZTTP. (B) d4TTP. (C) ddCTP. (D) 3TCTP. (E) NVP. (F) DLV. (G) EFV. (H) Alignment of partial sequences of HIV-1 p66, HIV-2, L1 and Ty1 RTs. Residues (101, 106, 181, 188, 190) important to NNRTI pocket motif are highlighted. Sequence from 122-174 is not shown.