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Conformational stability of dimeric HIV-1 and HIV-2 reverse transcriptases
G Divita1, K Rittinger, T Restle
1Max-Planck-Institut für Medizinische Forschung, Abteilung Biophysik, Heidelberg, Germany.
Biochemistry
|December 19, 1995
Summary
Human immunodeficiency virus (HIV) reverse transcriptase (RT) dissociation was studied using acetonitrile. Heterodimeric forms of HIV-1 and HIV-2 RT are more stable than homodimeric forms, with HIV-2 RT being the most stable.
Area of Science:
- Biochemistry
- Molecular Biology
- Virology
Background:
- Dimeric reverse transcriptase (RT) is essential for human immunodeficiency virus (HIV) replication.
- Understanding RT's structural dynamics is crucial for developing antiviral therapies.
Purpose of the Study:
- To investigate the dissociation of dimeric HIV-1 and HIV-2 reverse transcriptase (RT).
- To characterize the stability of homodimeric and heterodimeric RT forms.
- To explore the role of primer/template binding in RT stability.
Main Methods:
- Acetonitrile as a dissociating agent.
- Fluorescence spectroscopy, polymerase activity assays, and size-exclusion HPLC.
- Monitoring equilibrium transitions and conformational changes.
Main Results:
- RT dissociation leads to complete loss of polymerase activity and increased intrinsic fluorescence.
- Heterodimeric RT forms are more stable than homodimeric forms against dissociation.
- HIV-2 RT is more stable than HIV-1 RT, with higher free energy of dissociation.
- Primer/template binding significantly stabilizes the dimeric form of both RTs.
- Hydrophobic interactions are central to dimer formation.
Conclusions:
- The dissociation of HIV RT is a reversible two-state transition.
- Heterodimeric HIV-2 RT is the most stable form, offering potential therapeutic targets.
- Primer/template binding induces conformational changes that enhance RT stability.