Print Email Facebook Twitter Real-time detection of condensin-driven DNA compaction reveals a multistep binding mechanism Title Real-time detection of condensin-driven DNA compaction reveals a multistep binding mechanism Author Eeftens, J.M. (TU Delft BN/Cees Dekker Lab; Kavli institute of nanoscience Delft) Bisht, Shveta (European Molecular Biology Laboratory Heidelberg) Kerssemakers, J.W.J. (TU Delft BN/Technici en Analisten; Kavli institute of nanoscience Delft) Kschonsak, Marc (European Molecular Biology Laboratory Heidelberg) Haering, Christian H. (European Molecular Biology Laboratory Heidelberg) Dekker, C. (TU Delft BN/Cees Dekker Lab; Kavli institute of nanoscience Delft) Date 2017 Abstract Condensin, a conserved member of the SMC protein family of ring-shaped multi-subunit protein complexes, is essential for structuring and compacting chromosomes. Despite its key role, its molecular mechanism has remained largely unknown. Here, we employ single-molecule magnetic tweezers to measure, in real time, the compaction of individual DNA molecules by the budding yeast condensin complex. We show that compaction can proceed in large steps, driving DNA molecules into a fully condensed state against forces of up to 2 pN. Compaction can be reversed by applying high forces or adding buffer of high ionic strength. While condensin can stably bind DNA in the absence of ATP, ATP hydrolysis by the SMC subunits is required for rendering the association salt insensitive and for the subsequent compaction process. Our results indicate that the condensin reaction cycle involves two distinct steps, where condensin first binds DNA through electrostatic interactions before using ATP hydrolysis to encircle the DNA topologically within its ring structure, which initiates DNA compaction. The finding that both binding modes are essential for its DNA compaction activity has important implications for understanding the mechanism of chromosome compaction. Subject CondensinDNA compactionMagnetic tweezersSMC proteins To reference this document use: http://resolver.tudelft.nl/uuid:841b8ef1-dfcb-4265-b427-a9c2a1522f6f DOI https://doi.org/10.15252/embj.201797596 ISSN 0261-4189 Source The EMBO Journal, 36 (23), 3448 - 3457 Part of collection Institutional Repository Document type journal article Rights © 2017 J.M. Eeftens, Shveta Bisht, J.W.J. Kerssemakers, Marc Kschonsak, Christian H. Haering, C. Dekker Files PDF 3448.full.pdf 1.38 MB Close viewer /islandora/object/uuid:841b8ef1-dfcb-4265-b427-a9c2a1522f6f/datastream/OBJ/view