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Mycobacterium tuberculosis DNA gyrase possesses two functional GyrA-boxes
Aurélie Bouige1, Amélie Darmon, Jérémie Piton
1*UPMC Université Paris 06, ER5, EA 1541, Laboratoire de Bactériologie-Hygiène, 91 bd de l'Hôpital, F 75013 Paris, France.
The Biochemical Journal
|July 23, 2013
Summary
Mycobacterium tuberculosis DNA gyrase exhibits unique hybrid functions due to its C-terminal DNA-binding domain (CTD). A second motif, GyrA-box-like, enhances DNA decatenation activity, explaining its distinct mechanism.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Most bacteria have two type II topoisomerases: topoisomerase IV and DNA gyrase.
- Mycobacterium tuberculosis uniquely possesses only one, a hybrid DNA gyrase.
- Type IIA topoisomerase functional differences are linked to the C-terminal DNA-binding domain (CTD).
Purpose of the Study:
- To investigate the molecular mechanisms behind the hybrid functions of M. tuberculosis DNA gyrase.
- To analyze the structure and function of the M. tuberculosis GyrA CTD.
Main Methods:
- Sequence analysis
- Structural analysis of the GyrA CTD
- Biochemical experiments with the holoenzyme and isolated GyrA CTD
Main Results:
- The M. tuberculosis GyrA CTD shares structural similarity with other type IIA topoisomerases.
- A conserved GyrA-box motif is crucial for DNA supercoiling.
- A second motif, GyrA-box-like, confers enhanced DNA decatenation activity.
- Phylogenetic analysis provides insights into the functional diversity of bacterial type IIA topoisomerases.
Conclusions:
- The hybrid function of M. tuberculosis DNA gyrase is primarily attributed to its unique CTD structure and motifs.
- The GyrA-box-like motif's role in DNA decatenation is key to the enzyme's distinct mechanism.
- This study broadens understanding of type IIA topoisomerase functional diversity in bacteria.
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