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The twisted ‘life’ of DNA in the cell: bacterial topoisomerases
Author(s) -
Luttinger Amy
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.tb02369.x
Subject(s) - topoisomerase , dna supercoil , dna gyrase , biology , dna , chromosome segregation , circular bacterial chromosome , topoisomerase iv , chromosome , microbiology and biotechnology , genetics , escherichia coli , dna replication , gene
Summary DNA topoisomerases are essential to the cell for the regulation of DNA supercoiling levels and for chromosome decatenation. The proposed mechanisms for these reactions are essentially the same, except that a change in supercoiling is due to an intramolecular event, while decatenation requires an intermolecular event. The characterized bacterial topoisomerases appear capable of both types of reaction in vitro. Four DNA topoisomerases have been identified in Escherichia coli. Topoisomerase I, gyrase, and topoisomerase IV normally appear to have distinct essential functions within the cell, Gyrase and topoisomerase I are responsible for the regulation of DNA supercoiling. Both gyrase and topoisomerase IV are necessary for chromosomal decatenation. Multiple topoisomerases with distinct functions may give the cell more precise control over DNA topology by allowing tighter regulation of the principal enzymatic activities of these different proteins.