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Bacterial and archeal type I topoisomerases
1Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA. yuk-ching_tse-dinh@nymc.edu
Biochimica Et Biophysica Acta
|September 28, 1998
Summary
Bacterial and archaeal type IA topoisomerases regulate DNA topology and stability. Their diverse domain organization and torus-like transesterification domain are key to DNA cleavage and linking number changes.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Bacterial and archaeal type I topoisomerases (topoisomerase I, topoisomerase III, reverse gyrase) are crucial for DNA topology control.
- These enzymes play roles in regulating DNA supercoiling and maintaining genetic stability.
Purpose of the Study:
- To analyze the coding sequences and domain organization of type IA DNA topoisomerases across different organisms.
- To understand the structural basis for their enzymatic activity in DNA topology regulation.
Main Methods:
- Comparative analysis of coding sequences for type IA topoisomerases.
- Structural analysis of the conserved transesterification domain.
- Investigating the role of DNA substrate and Mg(II) cofactor binding in enzyme mechanism.
Main Results:
- Type IA topoisomerases exhibit variability in the organization of enzymatic domains.
- A conserved torus-like structure of the transesterification domain was identified.
- Active site tyrosine is crucial for DNA cleavage and rejoining.
Conclusions:
- The structural features of type IA topoisomerases, particularly the transesterification domain, are essential for their catalytic function.
- Enzyme conformational changes driven by substrate and cofactor binding are critical for altering DNA linking number.