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Published September 20, 2006 | public
Journal Article

Catalyzed relaxation of a metastable DNA fuel

Abstract

Practically all of life's molecular processes, from chemical synthesis to replication, involve enzymes that carry out their functions through the catalytic transformation of metastable fuels into waste products. Catalytic control of reaction rates will prove to be as useful and ubiquitous in nucleic-acid-based engineering as it is in biology. Here we report a metastable DNA "fuel" and a corresponding DNA "catalyst" that improve upon the original hybridization-based catalyst system (Turberfield et al. Phys. Rev. Lett. 90, 118102-1118102-4) by more than 2 orders of magnitude. This is achieved by identifying and purifying a fuel with a kinetically trapped metastable configuration consisting of a "kissing loop" stabilized by flanking helical domains; the catalyst strand acts by opening a helical domain and allowing the complex to relax to its ground state by a multistep pathway. The improved fuel/catalyst system shows a roughly 5000-fold acceleration of the uncatalyzed reaction, with each catalyst molecule capable of turning over in excess of 40 substrates. With k_(cat)/K_M ≈ 10^7/M/min, comparable to many protein enzymes and ribozymes, this fuel system becomes a viable component enabling future DNA-based synthetic molecular machines and logic circuits. As an example, we designed and characterized a signal amplifier based on the fuel-catalyst system. The amplifier uses a single strand of DNA as input and releases a second strand with unrelated sequence as output. A single input strand can catalytically trigger the release of more than 10 output strands.

Additional Information

© 2006 American Chemical Society. Received May 22, 2006. Publication Date (Web): August 26, 2006. We thank Richard W. Roberts for use of his Elutrap. G.S. was supported by the Swiss National Science Foundation and the Center for Biological Circuit design at Caltech. E.W. acknowledges NSF Awards #0093846, #0533064, and #0506468. B.Y. thanks the Moore Foundation for a Moore Distinguished Scholar Fellowship. Preliminary results for this work were previously reported.[37]

Additional details

Created:
August 19, 2023
Modified:
October 23, 2023