12 February 2016

Enzymes were imprisoned in DNA chambers

Alexander Enikeev, N+1 

Scientists from Arizona State University have built nanoscale chambers from DNA, inside which they placed enzymes. Experiments have shown that the activity of enzymes at the same time increased by 8 times. Article by Zhao et al. Nanocaged enzymes with enhanced catalytic activity and increased stability against protease digestion with the results of the work published in Nature Communications.

The researchers decided to reproduce the effect that occurs when enzymes are found in such relatively isolated parts of the cell as mitochondria, peroxisomes or the nucleus. To do this, the enzymes were placed in nanoscale chambers assembled from DNA.

Screenshot from Arizona State University press release
“Chemical cages: New technique advances synthetic biology" – VM.

The chambers were built in a buffer solution of viral DNA. The design of the cameras was developed using the caDNAno program. First, the scientists assembled two separate halves of the chamber, each of which contained one of two different enzymes. Then the halves of the chamber were joined together using short strands of DNA. Small molecules, for example, substrates involved in the enzymatic reaction, could freely penetrate into the chamber through nanopores.

Glucose oxidase and horseradish peroxidase were selected as enzymes for experiments, which catalyze a cascade of reactions, from glucose oxidation and the formation of hydrogen peroxide to the oxidation of ABTS, a chemical compound that is used to determine the rate of enzymatic reactions based on the observation of color changes.

The experimental results showed that the reaction activity inside the nanocambers was 8 times higher than that of the control enzymes that were not isolated. Scientists explained this effect by the fact that a large number of ordered hydrogen bonds were formed inside the DNA chambers due to the high density of phosphate groups. It was they who increased the stability of the enzyme molecules. The researchers tested this assumption by adding a solution of sodium chloride breaking hydrogen bonds, which reduced the activity of enzymes. In addition, nanocambers have demonstrated their effectiveness in protecting enzymes from destruction by trypsin.

Image of DNA chambers with enzymes inside, 
obtained by electron microscopy.
Illustration: Zhao Zhao, Nature Communications, 2016

DNA nanocamers can serve as molecular tools for changing the activity of enzymes and can be used in the field of smart materials and biotechnologies. In the future, scientists are sure, it will be possible to create programmable nanocamers from DNA molecules to create therapeutic nanodevices that regulate the functions of catalytic proteins.

DNA–based nanotechnology is a field of research in which they are engaged in the creation of artificial structures from nucleic acids for technological and engineering use that is not related to information encoding.

Portal "Eternal youth" http://vechnayamolodost.ru 12.02.2015

Found a typo? Select it and press ctrl + enter Print version