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DNA springs enable mechanical control of enzymatic reaction

An important precept of proposals for advanced nanotechnology/molecular manufacturing is that precisely applied mechanical force will control chemical reactions specifically enough to permit atomically precise construction of large (on a molecular scale), complex objects. Further, structural DNA nanotechnology, particularly scaffolded DNA origami, has been proposed to provide frameworks for use in nanotechnology to spatially organize functional components (see, for example “Modular DNA nanotubes provide programmable scaffolds for nanotechnology” and “Advancing nanotechnology by organizing functional components on addressable DNA scaffolds“.

Now, these two threads, mechanical control of chemical reactions and DNA nanotechnology have been brought together. Stuart Wolpert writes from the UCLA newsroom “UCLA physicists control chemical reactions mechanically“:

UCLA physicists have taken a significant step in controlling chemical reactions mechanically, an important advance in nanotechnology, UCLA physics professor Giovanni Zocchi and colleagues report.

Chemical reactions in the cell are catalyzed by enzymes, which are protein molecules that speed up reactions. Each protein catalyzes a specific reaction. In a chemical reaction, two molecules collide and exchange atoms; the enzyme is the third party, the “midwife to the reaction.”

But the molecules have to collide in a certain way for the reaction to occur. The enzyme binds to the molecules and lines them up, forcing them to collide in the “right” way, so the probability that the molecules will exchange atoms is much higher.

“Instead of just watching what the molecules do, we can mechanically prod them,” said Zocchi, the senior author of the research.

To do that, Zocchi and his graduate students, Chiao-Yu Tseng and Andrew Wang, attached a controllable molecular spring made of DNA to the enzyme. The spring is about 10,000 times smaller than the diameter of a human hair. They can mechanically turn the enzyme on and off and control how fast the chemical reaction occurs. In their newest research, they attached the molecular spring at three different locations on the enzyme and were able to mechanically influence different specific steps of the reaction.

Prof. Zocchi and his colleagues were aided in this study by their related work studying the elastic energy in their DNA molecular springs. These two strands of research point to the ability to apply specific forces to specific portions of a protein molecule to achieve specific alterations in reactivity.

Journal References (courtesy of ScienceDaily):
1. C.-Y. Tseng, A. Wang, G. Zocchi. Mechano-chemistry of the enzyme Guanylate Kinase. EPL (Europhysics Letters), 2010; 91 (1): 18005 http://dx.doi.org/10.1209/0295-5075/91/18005
2. Hao Qu, Chiao-Yu Tseng, Yong Wang, Alex J. Levine, Giovanni Zocchi. The elastic energy of sharply bent nicked DNA. EPL (Europhysics Letters), 2010; 90 (1): 18003 http://dx.doi.org/10.1209/0295-5075/90/18003

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