Related Experiment Video
Updated: Dec 30, 2025
09:16
In Vitro Directed Evolution of a Restriction Endonuclease with More Stringent Specificity
Published on: March 25, 2020
7.7K
Functional interactions between gyrase subunits are optimized in a species-specific manner
Daniela Weidlich1, Dagmar Klostermeier1
1Institute for Physical Chemistry, University of Muenster, Corrensstrasse 30, D-48149 Muenster, Germany.
The Journal of Biological Chemistry
|January 19, 2020
Summary
Bacterial DNA gyrase activity varies by species. While Bacillus subtilis and E. coli gyrases are highly active, Mycobacterium tuberculosis gyrase shows limited function, impacting DNA supercoiling and decatenation. Species-specific elements influence enzyme interactions.
Area of Science:
- Bacteriology
- Molecular Biology
- Enzymology
Background:
- DNA gyrase, a bacterial type II topoisomerase, is essential for DNA replication, transcription, and repair.
- It catalyzes ATP-dependent negative supercoiling and DNA decatenation, crucial for managing DNA topology.
- The enzyme's heterotetrameric structure (GyrA2GyrB2) is conserved, but species-specific variations influence its function.
Purpose of the Study:
- To compare the enzymatic activities of DNA gyrases from Bacillus subtilis, Escherichia coli, and Mycobacterium tuberculosis.
- To investigate the functional interactions between homologous and heterologous gyrase subunits.
- To elucidate how species-specific structural elements affect DNA gyrase function and ATP hydrolysis.
Main Methods:
- Comparative biochemical assays of purified DNA gyrase enzymes from B. subtilis, E. coli, and M. tuberculosis.
- Reconstitution of heterologous gyrase enzymes using subunits from different bacterial species.
- Measurement of DNA supercoiling, DNA decatenation, and ATPase activities.
Main Results:
- B. subtilis and E. coli DNA gyrases exhibited high ATPase, supercoiling, and decatenation activities.
- M. tuberculosis DNA gyrase showed significantly lower ATPase and catalytic activities.
- Heterologous gyrase combinations were generally less active, with a notable exception: a B. subtilis GyrB/M. tuberculosis GyrA hybrid enzyme displayed enhanced activity, suggesting M. tuberculosis GyrB limits ATP hydrolysis.
Conclusions:
- Species-specific structural features in E. coli and M. tuberculosis gyrase subunits may hinder efficient heterologous interactions.
- The limited activity of M. tuberculosis gyrase is primarily attributed to its GyrB subunit's inefficient ATP hydrolysis.
- Understanding these species-specific adaptations could inform the development of targeted gyrase inhibitors.
Related Concept Videos
01:29Cytoskeletal Proteins in Bacteria
4.0K
Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
4.0K
01:29Coordination of Gene Expression Processes in Bacteria
504
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
504
01:57Protein Complexes with Interchangeable Parts
2.8K
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order...
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order...
2.8K
00:43Bacterial RNA Polymerase
32.3K
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
32.3K
02:02DNA Topoisomerases
34.4K
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
34.4K
01:13Introduction to Mechanisms of Enzyme Catalysis
10.3K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
10.3K