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Function
Topoisomerase IV in S. pneumoniae is a paralogue of type II topoisomerase. Its main function is to regulate the level of DNA supercoiling within the cell so that replication, transcription, and repair can take place.
Type II topoisomerases undergo a strand-passage mechanism to remove supercoiling and disentangle chromosomes. These enzymes cleave both strands of DNA and then pass a second duplex through the break using ATP. The cleaved strands are ligated together again and the two products are released from the enzyme.
Structural Description
The active site is a tetramer made up of ParC and ParE subunits. The ParC subunit contains an N-terminal DNA breakage-reunion domain, which is linked to C-terminal β-pinwheel domains. This favors the passage of DNA and DNA unlinking from the complex. In contrast, the N-terminal of the ParE subunits forms the ATPase domain. Topoisomerase IV forms a complex with gyrase and works in tandem to remove DNA supercoiling and disentangle chromosomes.
Structure Insights
Evolutionarily Related Proteins
Available Structures
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