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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Many years ago Crick and Klug suggested that sharp bends or kinks have to facilitate strong bending of the double-helix, and accurate theoretical analysis confirms this suggestion. It remains, however, to be determined what is the critical curvature of DNA that prompts the appearance of the kinks. Different experimental approaches to the problem will be briefly reviewed. Attention will be paid to influence of the torsional stress in the double helix on the kink formation. The most reliable data suggest that the stable kinks appear only in torsionally relaxed DNA circles smaller than 70 bp. It is possible that the kinks represent openings of isolated base pairs. Although the probability of these openings in long unstressed DNA molecules is close to 10-5, it increases sharply in small DNA circles reaching 1 open bp per circle of 70 bp.
