How topoisomerase IV can efficiently unknot and decatenate negatively supercoiled DNA molecules without causing their torsional relaxation.

Détails

Ressource 1Télécharger: 27106058_BIB_0E0CBB4E996B.pdf (3192.89 [Ko])
Etat: Serval
Version: Final published version
ID Serval
serval:BIB_0E0CBB4E996B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
How topoisomerase IV can efficiently unknot and decatenate negatively supercoiled DNA molecules without causing their torsional relaxation.
Périodique
Nucleic acids research
Auteur(s)
Rawdon E.J., Dorier J., Racko D., Millett K.C., Stasiak A.
ISSN
1362-4962 (Electronic)
ISSN-L
0305-1048
Statut éditorial
Publié
Date de publication
02/06/2016
Peer-reviewed
Oui
Volume
44
Numéro
10
Pages
4528-4538
Langue
anglais
Notes
Publication types: Journal Article
Publication Status: ppublish
Résumé
Freshly replicated DNA molecules initially form multiply interlinked right-handed catenanes. In bacteria, these catenated molecules become supercoiled by DNA gyrase before they undergo a complete decatenation by topoisomerase IV (Topo IV). Topo IV is also involved in the unknotting of supercoiled DNA molecules. Using Metropolis Monte Carlo simulations, we investigate the shapes of supercoiled DNA molecules that are either knotted or catenated. We are especially interested in understanding how Topo IV can unknot right-handed knots and decatenate right-handed catenanes without acting on right-handed plectonemes in negatively supercoiled DNA molecules. To this end, we investigate how the topological consequences of intersegmental passages depend on the geometry of the DNA-DNA juxtapositions at which these passages occur. We observe that there are interesting differences between the geometries of DNA-DNA juxtapositions in the interwound portions and in the knotted or catenated portions of the studied molecules. In particular, in negatively supercoiled, multiply interlinked, right-handed catenanes, we detect specific regions where DNA segments belonging to two freshly replicated sister DNA molecules form left-handed crossings. We propose that, due to its geometrical preference to act on left-handed crossings, Topo IV can specifically unknot supercoiled DNA, as well as decatenate postreplicative catenanes, without causing their torsional relaxation.

Mots-clé
DNA/chemistry, DNA/metabolism, DNA Topoisomerase IV/chemistry, DNA Topoisomerase IV/metabolism, Models, Molecular, Monte Carlo Method, Nucleic Acid Conformation
Pubmed
Open Access
Oui
Création de la notice
10/05/2016 18:44
Dernière modification de la notice
08/05/2019 14:25
Données d'usage