DNA GYRASE AND TOPOISOMERASE-IV - BIOCHEMICAL ACTIVITIES, PHYSIOLOGICAL ROLES DURING CHROMOSOME-REPLICATION, AND DRUG SENSITIVITIES

DNA gyrase and topoisomerase IV are the two type II topoisomerases pre sent in bacteria. Though clearly related, based on amino acid sequence similarity, they each play crucial, but distinct, roles in the cell. Gyrase is involved primarily in supporting nascent chain elongation du ring replication of the chromosome, whereas topoisomerase IV separates the topologically linked daughter chromosomes during the terminal sta ge of DNA replication. These different roles can be attributed to diff erences in the biochemical properties of the two enzymes. The biochemi cal activities, physiological roles, and drug sensitivities of the enz ymes are reviewed. 0167-4781/98/$ - see front matter (C) 1998 Elsevier Science B.V. All rights reserved.