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Expression and purification of retroviral HIV-1 reverse transcriptase
1Department of Antiviral Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
Methods in Enzymology
|January 1, 1996
Summary
A new method purifies HIV-1 reverse transcriptase (RT) by mixing p51 and p66 subunits, preventing E. coli protease cleavage. This yields pure, active enzyme for drug sensitivity and kinetic studies.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- HIV-1 reverse transcriptase (RT) is a key therapeutic target.
- Expression in E. coli often leads to heterogeneous, proteolytically cleaved enzyme.
- Obtaining pure, active enzyme is crucial for structural and functional studies.
Purpose of the Study:
- To develop a purification protocol for homogeneous HIV-1 RT p66/p51 heterodimers.
- To overcome challenges of bacterial protease degradation during enzyme expression.
- To enable structural and biochemical characterization of active HIV-1 RT.
Main Methods:
- Co-expression and rapid association of truncated p51 with p66 subunits.
- Utilizing a p51 subunit truncated N-terminal to bacterial cleavage sites.
- Purification of the stable p66/p51 heterodimer resistant to proteolytic cleavage.
Main Results:
- A method was established to isolate pure, homogeneous HIV-1 RT p66/p51 heterodimers.
- The purified enzyme yielded crystals diffracting to 3.2-A resolution.
- The purified enzyme was used to study drug sensitivity (AZT triphosphate) and inhibitor kinetics (L-743,726).
Conclusions:
- The presented protocol effectively purifies active HIV-1 RT, avoiding E. coli protease degradation.
- This method facilitates structural and functional studies of HIV-1 RT and related lentiviral RTs.
- The approach is likely adaptable for purifying reverse transcriptases from other lentiviruses.