Accordion made of DNA
Biochemists have taken a big step towards creating DNA computers
American biochemists have learned to weave DNA strands into a kind of "accordion" that can be used as basic elements for biological computers of the future, according to an article published in the journal Science (Song et al., Reconfiguration of DNA molecular arrays driven by information relay).
"As a rule, modern computing systems based on DNA are in solution not in assembled form, but in the form of a set of disparate molecules that store information and float freely in solution. We managed to take the next step – to link all the DNA strands together and turn them into a physical machine," says Yonggang Ke from Emory University in Atlanta (in a press release Switchable DNA mini–machines store information - VM).
Today, most experiments with DNA-based nanomachines use a special class of methods for their assembly, which in the scientific community are known collectively as "DNA origami". In this technique, the basis for any details of biomachines is a long single DNA chain, which is woven into the desired three–dimensional object using short "hairpins" of several nucleotides - DNA bricks.
In recent years, biochemists have woven dozens of different machines from short DNA strands, including forceps, drug delivery systems to certain cells of the body, and even primitive robots-"transformers" and the simplest computers. The development of DNA origami has not progressed beyond this for several reasons - it is very difficult to assemble complex structures from DNA strands, and it is even more difficult to manage and change their structure.
Ke and his colleagues found a way to solve this problem by learning how to combine DNA strands into structures similar in shape to doors-"accordion" in buses or, as biochemists themselves put it, accordion furs. Each segment of such a DNA "door" consists of several crossed strands, the position of which in space depends on how adjacent blocks are located.
Thanks to this, such DNA origami retain stability and shape even if they are attached to some other molecule or a solid surface, and at the same time they remain mobile and capable of compression and "straightening".
Accordingly, by combining several similar "harmonicas" of different shapes and sizes, it is possible to create complex structures that respond to external stimuli and work on the same principles as transistors in conventional computers. Their main difference will be that the "carrier" of information here will not be electrons, but short single strands of DNA that attach to special areas on the origami surface and force them to change their shape.
In addition to biocomputers, these same "harmonicas", as Ke says, can be used to create full-fledged nanomachines consisting of many moving parts interacting with each other. Both, scientists hope, will help make nanomachines more useful and practical than they are today.
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23.06.2017