Folding transition of large DNA completely inhibits the action of a restriction endonuclease as revealed by single-chain observation.
The biochemical characteristics of lambda DNA chains in folded/unfolded states upon cleavage by the restriction enzyme ApaLI were investigated in the presence of spermine. These characteristics of DNA chains depending on their higher-order structure were studied at the single-molecule level using fluorescence microscopy. With a low concentration of spermine, lambda DNA takes a random coiled conformation and allows digestion by the enzyme, while under a high concentration of spermine, lambda DNA takes a compact folded structure and inhibits such attack. Together with comparative experiments on short oligomeric DNA, our results suggest that the transition in the higher-order structure causes on/off-type switching of sensitivity to the enzyme.
Oana
Hidehiro
H
Department of Physics, Kyoto University & CREST, Japan. oana@scphys.kyoto-u.ac.jp
Tsumoto
Kanta
K
Yoshikawa
Yuko
Y
Yoshikawa
Kenichi
K
D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004262:DNA Restriction Enzymes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009690:Nucleic Acid Conformation; D013050:Spectrometry, Fluorescence; D013096:Spermine / Q000378:metabolism
D013096:Spermine; D004247:DNA; D004262:DNA Restriction Enzymes