Related Experiment Videos
Mutational analysis of two conserved sequence motifs in HIV-1 reverse transcriptase.
1Department of Molecular Sciences, Wellcome Research Laboratories, Beckenham, Kent, U.K.
FEBS Letters
|May 6, 1991
Summary
Mutations in HIV-1 reverse transcriptase conserved regions affect enzyme activity. Specific mutations at aspartates 185/186 abolish activity, while altering tyrosine-183 impacts substrate and inhibitor binding.
Area of Science:
- Biochemistry
- Molecular Biology
- Virology
Background:
- HIV-1 reverse transcriptase is crucial for viral replication.
- Specific sequence motifs within the enzyme are vital for its catalytic function.
Purpose of the Study:
- To investigate the functional roles of conserved sequence motifs in HIV-1 reverse transcriptase.
- To elucidate the impact of specific mutations on enzyme activity and substrate binding.
Main Methods:
- Site-directed mutagenesis was employed on the cloned HIV-1 reverse transcriptase gene.
- Mutant proteins were analyzed for catalytic activity and template-primer binding.
- Kinetic parameters (Km, Ki) were determined for specific mutants.
Main Results:
- Mutations of aspartates at positions 185 and 186 resulted in catalytically inactive enzymes that retained template-primer binding.
- Other mutations in conserved regions led to reduced reverse transcriptase activity.
- Mutation of tyrosine-183 to serine significantly increased Km for dTTP and Ki for various inhibitors.
Conclusions:
- Conserved residues in HIV-1 reverse transcriptase motifs are critical for catalysis.
- Aspartates 185/186 are essential for catalytic activity.
- Tyrosine-183 plays a role in substrate and inhibitor interactions, influencing enzyme kinetics.