Mutagenesis of Gln294 of the reverse transcriptase of human immunodeficiency virus type-2 and its effects on the ribonuclease H activity.
Despite the high homology between human immunodeficiency virus type-1 (HIV-1) and human immunodeficiency virus type-2 (HIV-2) reverse transcriptases (RTs), the ribonuclease H (RNase H) level of HIV-2 RT is lower than that of HIV-1 RT, while the DNA polymerase of both RTs is similar. We conducted mutagenesis of HIV-2 RT Gln294 (shown to control the RNase H activity level when modified to a Pro in the smaller p54 subunit and not in the larger p68 subunit) to various residues, and assayed the activities of all mutants. All exhibited an RNase H that is higher than the wild-type (WT) HIV-2 RT level, although the DNA polymerase of all mutants equals WT HIV-2 RT level. These results represent a unique case, where every mutation induces an increase rather than a decrease in an enzyme's activity.
Bochner
R
R
Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 62263, Israel.
Duvshani
A
A
Adir
N
N
Hizi
A
A
D019943:Amino Acid Substitution; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D016296:Mutagenesis; D011487:Protein Conformation; D016914:Ribonuclease H / Q000235:genetics* / Q000378:metabolism*
D005973:Glutamine; C072416:reverse transcriptase, Human immunodeficiency virus 2; D054303:HIV Reverse Transcriptase; D004259:DNA-Directed DNA Polymerase; D016914:Ribonuclease H