Topoisomerase V relaxes supercoiled DNA by a constrained swiveling mechanism
Autor: | Alfonso Mondragón, Alexei I. Slesarev, John F. Marko, Bernhard Schnurr, Bhupesh Taneja |
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Rok vydání: | 2007 |
Předmět: |
Models
Molecular Magnetic tweezers Optical Tweezers Protein Conformation Euryarchaeota Magnetics chemistry.chemical_compound Protein structure Vaccinia Deinococcus Gene chemistry.chemical_classification Likelihood Functions Multidisciplinary biology DNA Superhelical Topoisomerase Biological Sciences biology.organism_classification Molecular biology Enzyme DNA Topoisomerases Type I chemistry Calibration Biophysics biology.protein DNA supercoil DNA |
Zdroj: | Proceedings of the National Academy of Sciences. 104:14670-14675 |
ISSN: | 1091-6490 0027-8424 |
Popis: | Topoisomerase V is a type I topoisomerase without structural or sequence similarities to other topoisomerases. Although it belongs to the type I subfamily of topoisomerases, it is unrelated to either type IA or IB enzymes. We used real-time single-molecule micromechanical experiments to show that topoisomerase V relaxes DNA via events that release multiple DNA turns, employing a constrained swiveling mechanism similar to that for type IB enzymes. Relaxation is powered by the torque in the supercoiled DNA and is constrained by friction between the protein and the DNA. Although all type IB enzymes share a common structure and mechanism and type IA and type II enzymes show marked structural and functional similarities, topoisomerase V represents a different type of topoisomerase that relaxes DNA in a similar overall manner as type IB molecules but by using a completely different structural and mechanistic framework. |
Databáze: | OpenAIRE |
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