title: DNA cleavage site selection by Type III restriction enzymes provides evidence for head-on protein collisions following 1D bidirectional motion.
abstract: DNA cleavage by the Type III Restriction-Modification enzymes requires communication in 1D between two distant indirectly-repeated recognitions sites, yet results in non-specific dsDNA cleavage close to only one of the two sites. To test a recently proposed ATP-triggered DNA sliding model, we addressed why one site is selected over another during cleavage. We examined the relative cleavage of a pair of identical sites on DNA substrates with different distances to a free or protein blocked end, and on a DNA substrate using different relative concentrations of protein. Under these conditions a bias can be induced in the cleavage of one site over the other. Monte-Carlo simulations based on the sliding model reproduce the experimentally observed behaviour. This suggests that cleavage site selection simply reflects the dynamics of the preceding stochastic enzyme events that are consistent with bidirectional motion in 1D and DNA cleavage following head-on protein collision.
authors: Biotechnology Center, Dresden University of Technology, 01062 Dresden, Germany.
authors: Friedrich W
authors: FW
authors: Schwarz
authors: Kara
authors: K
authors: van Aelst
authors: Júlia
authors: J
authors: Tóth
authors: Ralf
authors: R
authors: Seidel
authors: Mark D
authors: MD
authors: Szczelkun
mesh_terms: D004247:DNA / Q000378:metabolism; D053837:DNA Cleavage; D015263:Deoxyribonucleases, Type III Site-Specific / Q000378:metabolism*; D008954:Models, Biological; D009010:Monte Carlo Method; D009038:Motion
chemical_list: D004247:DNA; C093225:DNA restriction enzyme EcoPI; D015263:Deoxyribonucleases, Type III Site-Specific