Single Molecular Images of DNA Catenanes Observed by AFM

Preparation of dimeric DNA catenane by the reaction of topoisomerase I to the nicked DNA in the presence of circular DNA. 

17 Agarose gel electrophoresis of the reaction mixture between nicked DNA and circular DNA in the presence of topoisomerase I. [Topoisomerase I] 0.05 unit/ xL (lanes 1 and 2), 0.1 unit/ xL (lanes 3 and 4). Lane 1 and lane 3 include nicked DNA. The concentration of circular DNA was fixed at 14 ng/ xL. 

DNA [ii]Catenanes Prepared by Irreversible Reaction with DNA Ligase 

DNA catenanes prepared by the addition of T4 DNA ligase to a mixture of linear and nicked (open circular) DNAs. 

To obtain in situ chemical information about the organic components in the biominerals, we tried using solid state Fig. 4.20(a) shows the solid 

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