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Mechanism and fidelity of HIV reverse transcriptase
W M Kati1, K A Johnson, L F Jerva
1Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
The Journal of Biological Chemistry
|December 25, 1992
Summary
Human immunodeficiency virus reverse transcriptase exhibits distinct RNA-dependent and DNA-dependent polymerase and ribonuclease H activities. Kinetic analysis reveals independent catalytic functions and high fidelity in nucleotide incorporation, crucial for understanding viral replication.
Area of Science:
- Biochemistry
- Molecular Biology
- Virology
Background:
- Human immunodeficiency virus reverse transcriptase (HIV RT) is a key enzyme in viral replication.
- Understanding its catalytic activities, including polymerase and ribonuclease H functions, is crucial for developing antiviral therapies.
Purpose of the Study:
- To kinetically characterize the RNA-dependent and DNA-dependent polymerase and ribonuclease H activities of HIV RT.
- To elucidate the enzyme's mechanism of nucleotide incorporation and primer/template interaction.
Main Methods:
- Rapid transient kinetic methods were employed.
- Defined synthetic DNA/RNA and DNA/DNA primer/templates were used.
- Nucleoside triphosphate incorporation and RNA cleavage rates were analyzed.
Main Results:
- HIV RT demonstrated independent polymerase and ribonuclease H activities.
- The enzyme exhibited high fidelity in nucleotide misincorporation, with distinct discrimination against incorrect nucleoside triphosphates.
- Kinetic analysis revealed a two-step nucleoside triphosphate binding mechanism.
Conclusions:
- The distinct catalytic activities and high fidelity of HIV RT are essential for its function in viral replication.
- Kinetic insights into HIV RT mechanism can inform the design of novel antiviral drugs targeting reverse transcription.