Biophysical Journal 84 6

Cover: Structure of NgoMIV restriction endonuclease with two bound DNA fragments. Protein α-helices are shown in green, β-strands in yellow, and the DNA backbone is shown in purple. NgoMIV binds double-stranded DNA at two restriction sites simultaneously by looping DNA. A single molecule ?uorescence resonance energy transfer study of the DNA looping process using this endonuclease and linear double-stranded DNA molecule labeled with Cy3 and Cy5 dyes is described by Katiliene et. al. on p. 4053–4061.