Interaction of tRNALys with the p66/p66 form of HIV-1 reverse transcriptase stimulates DNA polymerase and ribonuclease H activities.
The precursor homodimeric p66/p66 form of human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) possesses the DNA polymerase and RNase H activities involved in the synthesis of the double-stranded provirus DNA. Reverse transcription is initiated from tRNALys in the case of HIV-1. The present study confirmed that interactions between HIV-1 RT and tRNALys induce protein conformational changes and demonstrated that these interactions stimulate the enzymatic activities associated with the p66 subunit. Thus, the p66/p66 form of the enzyme is strongly stimulated in both DNA polymerase and RNase H activities. Preincubation of the enzyme with tRNA is an obligatory step to obtain the stimulatory effect. The affinity of template, primer, or substrate for RT p66/p66 did not change when the enzyme was preincubated with tRNALys at stimulatory concentrations; the interaction of tRNA with p66/p66 has an effect only on the maximal rate of polymerization. It is further shown that the RNase H domain of RT is much more accessible to protease attack than the DNA polymerase active site.
Andreola
M L
ML
Institut de Biochemie Cellulaire et Neurochimie du Centre National de la Recherche Scientifique, Bordeaux, France.
Nevinsky
G A
GA
Barr
P J
PJ
Sarih-Cottin
L
L
Bordier
B
B
Fournier
M
M
Litvak
S
S
Tarrago-Litvak
L
L
D002918:Chymotrypsin / Q000494:pharmacology; D004789:Enzyme Activation; D015497:HIV-1 / Q000201:enzymology*; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D011485:Protein Binding; D011487:Protein Conformation; D011498:Protein Precursors / Q000378:metabolism; D012357:RNA, Transfer, Lys / Q000378:metabolism*; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism* / Q000648:ultrastructure; D011994:Recombinant Proteins / Q000378:metabolism; D016914:Ribonuclease H / Q000378:metabolism
D046911:Macromolecular Substances; D011498:Protein Precursors; D012357:RNA, Transfer, Lys; D011994:Recombinant Proteins; D012194:RNA-Directed DNA Polymerase; D016914:Ribonuclease H; D002918:Chymotrypsin