title: Structural similarities between topoisomerases that cleave one or both DNA strands.
abstract: Type IA and type II DNA topoisomerases are distinguished by their ability to cleave one or two strands, respectively, of a DNA duplex. Both types have been proposed to use an "enzyme-bridging" mechanism, in which a break is formed in a DNA strand and a gap is opened between the broken pieces to allow passage of a second DNA strand or duplex segment. Although the type IA and type II topoisomerase structures appear overall quite different from one another, unexpected similarities between several structural elements suggest that members of the two subfamilies may use comparable mechanisms to bind and cleave DNA.
authors.affiliation: Whitehead Institute, 9 Cambridge Center, Cambridge, MA 02142, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Berger
authors.forename: D
authors.initials: D
authors.lastname: Fass
authors.forename: J C
authors.initials: JC
authors.lastname: Wang
authors.forename: S C
authors.initials: SC
authors.lastname: Harrison
mesh_terms: D001665:Binding Sites; D004264:DNA Topoisomerases, Type I / Q000737:chemistry* / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000737:chemistry* / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004926:Escherichia coli; D017510:Protein Folding; D013329:Structure-Activity Relationship
chemical_list: D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D004264:DNA Topoisomerases, Type I; D004250:DNA Topoisomerases, Type II