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Probing structure/function relationships of HIV-1 reverse transcriptase with styrene oxide N2-guanine adducts
E Forgacs1, G Latham, W A Beard
1Sealy Center for Molecular Science, The University of Texas Medical Branch, Galveston, Texas 77555-1071, USA.
The Journal of Biological Chemistry
|March 28, 1997
Summary
Human immunodeficiency virus (HIV-1) reverse transcriptase replication is blocked by DNA adducts near the alpha-helix H region. Mutations in this helix alter termination, indicating its role in monitoring DNA modifications.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Human immunodeficiency virus (HIV-1) reverse transcriptase is crucial for viral replication.
- Understanding enzyme-DNA interactions is key to developing antiviral therapies.
- DNA adducts can impede polymerase activity, affecting viral replication.
Purpose of the Study:
- To investigate the impact of DNA adducts on HIV-1 reverse transcriptase activity.
- To identify specific regions of the polymerase involved in recognizing DNA modifications.
- To elucidate the mechanism of adduct-induced replication termination.
Main Methods:
- Site-specific and stereospecific DNA modifications were introduced.
- Modified DNA fragments were used as templates for HIV-1 reverse transcriptase.
- Polymerase mutants in the alpha-helix H region were analyzed.
Main Results:
- DNA adducts induced replication termination at specific sites.
- Termination sites correlated with the position of alpha-helix H contact in the DNA minor groove.
- Mutations in alpha-helix H altered the probability of adduct-induced termination.
Conclusions:
- Alpha-helix H of HIV-1 reverse transcriptase plays a critical role in monitoring DNA modifications.
- The enzyme's alpha-helix H is sensitive to lesions in the minor groove of the template-primer DNA.
- These findings provide insights into the mechanism of HIV-1 reverse transcriptase fidelity and potential therapeutic targets.