Proposed models for DNA duplex breakage by Type I restriction enzymes on circular () and linear () DNA substrates

Copyright information:Taken from "On the DNA cleavage mechanism of Type I restriction enzymes"Nucleic Acids Research 2005;33(6):1760-1766.Published online 23 Mar 2005PMCID:PMC1069518.© The Author 2005. Published by Oxford University Press. All rights reserved For more explanation see Discussion. DNA is represented as two black lines. The methylase (M2S1) and HsdR (R) subunits are represented as light gray and dark gray ovals. The pairs of scissors indicate the position of DNA double-strand break.