Switching the mechanics of dsDNA by Cu salicylic aldehyde complexation.

DNA is increasingly employed as a programmable building block for nanoscale structures. Self-assembly via specific DNA base-pair recognition allows an unparalleled variety of structures to be formed. Subsequent stabilization of such structures may be desirable and can be accomplished by metal coordination bonds to substituted bases. We investigated the switching of the mechanics of dsDNA carrying salicylic aldehyde nucleosides upon copper complexation. We found the rupture force to increase by up to a factor of two. Furthermore we discovered that the strongly localized coordinative bond dominates the mechanics of this biomolecular hybrid for high loading rates, whereas at lower rates the broad binding potential of the DNA dominates the stability.