Mutational studies of human immunodeficiency virus type 1 reverse transcriptase: the involvement of residues 183 and 184 in the fidelity of DNA synthesis.
The high error rates characteristic of human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) are a presumptive source of the viral hypermutability that impedes prevention and therapy of acquired immunodeficiency syndrome (AIDS). We have analyzed two mutants of HIV-1 RT by conducting a comparative study of the accuracy of DNA synthesis. Each mutant bears a single amino acid substitution adjacent to the two aspartic acid residues at positions 185 and 186 in the highly conserved DNA polymerase active site. The first mutant, Met 184-->Leu (M184L), displays a marked reduction in both misinsertion and mispair extension, suggesting a fidelity of DNA synthesis significantly higher than that of the wild-type HIV-1 RT. The second mutant, Tyr 183-->Phe (Y183F), shows a decrease in mispair extension with no significant change in misincorporation. Thus, the overall pattern of error-proneness of DNA synthesis is: wild-type HIV-1 RT > Y183F > M184L. Taken together, it is possible that residues 183 and 184 contribute to the low fidelity of DNA synthesis characteristic of the reverse transcriptases of HIV-1, HIV-2 and possibly, of other lentiviruses. Our observations may bear on the nature of potential mutations responsible for resistance to the nucleoside analogs used in chemotherapy of AIDS.
Bakhanashvili
M
M
Department of Cell Biology and Histology, Sackler School of Medicine, Tel Aviv University, Israel.
Avidan
O
O
Hizi
A
A
D001483:Base Sequence; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis; D003838:Deoxyadenine Nucleotides / Q000378:metabolism; D003845:Deoxycytosine Nucleotides / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation; D012194:RNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D013942:Thymine Nucleotides / Q000378:metabolism
D004279:DNA, Viral; D003838:Deoxyadenine Nucleotides; D003845:Deoxycytosine Nucleotides; D003848:Deoxyguanine Nucleotides; D013942:Thymine Nucleotides; C024107:2'-deoxycytidine 5'-triphosphate; C029603:deoxyguanosine triphosphate; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase; C026600:2'-deoxyadenosine triphosphate; C024157:thymidine 5'-triphosphate