(ORDO NEWS) — DNA synthesis technologies have been known for several decades. They make it possible to obtain short molecules with the desired nucleotide sequence, using them as tools of genetics, biochemistry, and even to create ” molecular machines “.
For such construction, DNA is extremely convenient: it is a linear, stable and versatile polymer, the properties of which are easily controllable, since they depend on the sequence of simple monomer blocks. It was DNA that became the basis of the new fluorescent system, which is described in an article published in the journal Nature Methods .
Fluorescence serves as a convenient tool for biomedical research and technology. However, fluorescent pigments do not bind well to proteins. To solve this problem, scientists at the University of Montreal, Canada, turned to small synthetic DNA strands.
Such molecules, only a few nanometers long, are capable, on the one hand, of retaining the pigment, and on the other hand, they bind with high precision to one or another part of the protein. Thanks to this, “nanoantennas” allow tracking the work and the corresponding structural changes in the protein.
“Just as bi-directional radio allows radio waves to be received and transmitted, a fluorescent nanoantenna senses light of one color at one wavelength and transmits at another, depending on the state of the protein to which it is associated,” explains Alexis Vallée -Bélisle), lead author of the new work.
For example, some “nanoantennas” bind to a protein in the original conformation, “signaling” this with their color, while others – with a protein in an active form, demonstrating a different shade that is easily distinguishable under a microscope.
Also, scientists have developed a method for selecting the optimal sequence of nucleotides for DNA “nanoantennas”, suitable for different protein structures. Demonstrating the capabilities of the new system, with its help, they tracked the work of one of the most important enzymes of living cells – alkaline phosphatase – by tracing its transition between five conformational states.
Scientists were able to register even a short-lived transitional form in which the protein is bound to the initial substrate of the catalyzed reaction. In addition, nanoantennas have been demonstrated for the immunoglobulin binding protein G.
“What is most inspiring is the understanding that many laboratories around the world, equipped with a conventional spectrofluorimeter, can easily use such ‘nanoantennas’ to study the required proteins, to search for new drugs and to develop new nanotechnologies,” sums up Dominic Lauzon, one of the authors of the work.
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