Increasing the Thermal Stability of Self-Assembling DNA Nanostructures by Incorporation of isoG/isoC Base Pairs
K. Ho, H. Li, E.B. Roesch, C.B. Sherrill, J.R. Prudent and T.H. LaBean
Duke University, US
DNA nanostructure, self-assembly, isoG/isoC
Self-assembling DNA nanostructures are currently being developed for a variety of applications in nanofabrication and molecular computing. For many uses, these nanostructures would benefit from increased thermal stability. However, increasing the lengths of sticky-ends that encode interactions between building blocks (DNA tiles) could have an adverse effect on the observed rates of assembly errors and therefore be undesirable. An alternative approach described here, makes use of the recently developed, non-natural basepair isoG/isoC which provides specific complementary pairing with three hydrogen bonds and interaction strength comparable to G/C pairing. In this study, two types of DNA cross tile lattice were compared 1) original design and 2) isoG/isoC design in which all A/T basepairs in the tile sticky-ends were substituted with isoG/isoC basepairs. We observed an increase in lattice melting temperature of approximately 11°C from Tm = 42±1°C to Tm = 53±1°C, and at the same time there was no change in the tile melting temperature (Tm = 62 ±1°C). We have successfully demonstrated a marked increase in the thermal stability of a complex DNA nanostructure via the incorporation of isoG/isoC basepairs. Future studies will include incorporation of isoG/isoC within the tile building blocks in order to increase tile stability.
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Nanotech 2006 Conference Program Abstract