Type III restriction enzymes communicate in 1D without looping between their target sites.
To cleave DNA, Type III restriction enzymes must communicate the relative orientation of two asymmetric recognition sites over hundreds of base pairs. The basis of this long-distance communication, for which ATP hydrolysis by their helicase domains is required, is poorly understood. Several conflicting DNA-looping mechanisms have been proposed, driven either by active DNA translocation or passive 3D diffusion. Using single-molecule DNA stretching in combination with bulk-solution assays, we provide evidence that looping is both highly unlikely and unnecessary, and that communication is strictly confined to a 1D route. Integrating our results with previous data, a simple communication scheme is concluded based on 1D diffusion along DNA.
Ramanathan
Subramanian P
SP
BIOTEChnology Center Dresden, Dresden University of Technology, 01062 Dresden, Germany.
van Aelst
Kara
K
Sears
Alice
A
Peakman
Luke J
LJ
Diffin
Fiona M
FM
Szczelkun
Mark D
MD
Seidel
Ralf
R
D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015263:Deoxyribonucleases, Type III Site-Specific / Q000378:metabolism*; D004058:Diffusion; D006868:Hydrolysis; D008956:Models, Chemical; D009690:Nucleic Acid Conformation; D052898:Optical Tweezers; D013379:Substrate Specificity
D004247:DNA; D015263:Deoxyribonucleases, Type III Site-Specific