Читать книгу Structure and Function of the Bacterial Genome - Charles J. Dorman - Страница 18

Bidirectional replication produces two interlinked copies of the chromosome and these must be decatenated before they can be segregated at cell division. Decatenation of fully intact duplexes is an intermolecular event that is catalysed by type II topoisomerases. Topoisomerase IV is the most efficient decatenase in such cases (Adams et al. 1992; Espéli et al. 2003; Zechiedrich and Cozzarelli 1995), although DNA gyrase can provide this function too (Steck and Drlica 1984). Type I topoisomerases can also supply a decatenase function, but in this case one of the DNA strands in at least one of the DNA duplexes must be nicked, with the topoisomerase providing the break in the intact strand of the same duplex to permit passage of the intact duplex through the gap (DiGate and Marians 1988).