Print Email Facebook Twitter Motor step size and ATP coupling efficiency of the dsDNA translocase EcoR124I Title Motor step size and ATP coupling efficiency of the dsDNA translocase EcoR124I Author Seidel, R. Bloom, J.G.P. Dekker, C. Szczelkun, M.D. Faculty Applied Sciences Department Kavli Institute of Nanoscience Delft Date 2008-04-03 Abstract The Type I restriction-modification enzyme EcoR124I is an archetypical helicase-based dsDNA translocase that moves unidirectionally along the 3'–5' strand of intact duplex DNA. Using a combination of ensemble and single-molecule measurements, we provide estimates of two physicochemical constants that are fundamental to a full description of motor protein activity—the ATP coupling efficiency (the number of ATP consumed per base pair) and the step size (the number of base pairs transported per motor step). Our data indicate that EcoR124I makes small steps along the DNA of 1 bp in length with 1 ATP consumed per step, but with some uncoupling of the ATPase and translocase cycles occurring so that the average number of ATP consumed per base pair slightly exceeds unity. Our observations form a framework for understanding energy coupling in a great many other motors that translocate along dsDNA rather than ssDNA. Subject ATPasehelicasemolecular motorsingle moleculestopped flow To reference this document use: http://resolver.tudelft.nl/uuid:2004af16-a103-4fff-bb59-57888a96d2dc Publisher Nature Publishing Group ISSN 0261-4189 Source EMBO Journal, 27 (9), 2008 Part of collection Institutional Repository Document type journal article Rights (c) 2008 The Author(s) ; European Molecular Biology Organization Files PDF Seidel_2008.pdf 536.61 KB Close viewer /islandora/object/uuid:2004af16-a103-4fff-bb59-57888a96d2dc/datastream/OBJ/view