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Retroviral integrases and their cousins
P Rice1, R Craigie, D R Davies
1Laboratory of Molecular Biology,National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0540, USA.
Current Opinion in Structural Biology
|February 1, 1996
Summary
Structural similarities among HIV integrase, avian sarcoma virus integrase, and Mu transposase suggest a shared catalytic mechanism for these polynucleotidyl transferases. These enzymes cut DNA, with integrase and transposase also splicing DNA strands.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biology
Background:
- HIV integrase, avian sarcoma virus integrase, and Mu transposase are key enzymes in viral replication and genetic transposition.
- Previous studies have characterized the individual functions of these enzymes, but their structural relationships were not fully elucidated.
Purpose of the Study:
- To compare the structures of the catalytic domains of HIV integrase, avian sarcoma virus integrase, and Mu transposase.
- To identify structural similarities and potential shared catalytic mechanisms among these enzymes and other nucleases.
Main Methods:
- X-ray crystallography was used to determine the three-dimensional structures of the catalytic domains.
- Comparative structural analysis was performed to identify conserved features and similarities.
Main Results:
- The catalytic domains of HIV integrase, avian sarcoma virus integrase, and Mu transposase exhibit striking structural similarity.
- These enzymes share significant structural homology with known nucleases, indicating a common structural fold.
- All studied enzymes cleave polynucleotides, generating 3'OH and 5'PO4 termini.
Conclusions:
- The conserved structural features suggest a shared catalytic mechanism for this superfamily of polynucleotidyl transferases.
- Integrase and transposase enzymes possess strand-transfer activity, enabling DNA splicing.
- Structural insights provide a foundation for understanding the function and evolution of these critical enzymes.