University of Manchester researchers have created a molecular machine that can assemble four different chemical products:
David A. Leigh of the University of Manchester and coworkers made molecular-machine-based chemical synthesis a reality four years ago when they developed a large molecule that picks up amino acids and assembles them into tripeptides (Science 2013, DOI: 10.1126/science.1229753). Now, they've taken the concept to another level by creating a programmable molecular machine that creates four different products by adding thiol and alkene substituents asymmetrically to an α,β-unsaturated aldehyde substrate (Nature 2017, DOI: 10.1038/nature23677). The machine makes each of the products with stereoselectivity similar to, but in some cases lower than, that of corresponding catalytic reactions in solution, Leigh says.
To generate the products, Leigh and coworkers attach an α,β-unsaturated aldehyde substrate to an "arm" in the molecular machine. An acyl hydrazone located in the center of the machine changes conformation in response to pH changes, causing the arm to rotate between two fixed orientations. Rotations position the substrate above one or another of two silyl prolinol activation sites in the machine that mediate reactions with opposite chirality—R for one site, S for the other. So arm position controls reaction chirality.
The substrate forms a reactive iminium intermediate with an activation site, and the intermediate then reacts with a thiol for the first addition. Then the substrate, with its added sulfide, forms a reactive enamine with an activation site, and the alkene adds to that. If the arm is rotated between the two activation sites mid-synthesis by adding acid, the steps have opposite chirality, and the diastereomer products have (R,S) or (S,R) configuration. If the arm is stationary between steps, both additions occur with the same chirality, and the product has (R,R) or (S,S) configuration.
(Score: 0) by Anonymous Coward on Monday September 25 2017, @01:25PM (2 children)
Software choosing what to make on one end.
Assembled and verified molecules coming out the other end.
Still, this is a step towards the biological machinery that has been working for eons.
(Score: 1) by shrewdsheep on Monday September 25 2017, @01:55PM (1 child)
Yes, but without the abstraction. Biology has abstract layers of code (DNA) and machines (proteins). Still DNA cannot be programmed at will because the programming language lacks abstraction. As a computer analogy, the study feels like a hack written in assembly while using a CPU bug to be more efficient. Hacking the DNA would be like using brainfuck to achieve the task. What we need is what you describe: a specification and an algorithm that produces the corresponding machinery as in declarative programming. I am not fully convinced that the study brings us closer to that goal.
(Score: 1, Interesting) by Anonymous Coward on Monday September 25 2017, @03:32PM
Sounds like you are suggesting we need a biological computer.
I'm suggesting we need to be able to make molecules under the precise control of the electronic computers we already have.
Once that tool works, the a biological computer could be one of many possible projects.
(Score: 3, Funny) by c0lo on Monday September 25 2017, @01:54PM (1 child)
TFS seems to be English, but I reckon it still requires translation for the unusual-fetish swear words.
Yeap, the "thiol" and "α,β-unsaturated aldehyde" and "reactive enamine", those are the ones; should be a heavily unusual kinda porn, a google-search for "rule 34 unsaturated aldehyde" got images showing some kind of stick figures, hardly sexual in nature.
(grin)
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by HiThere on Monday September 25 2017, @04:41PM
Funny, my search for rule 34 unsaturated aldehyde
https://www.google.com/search?q=rule+34+unsaturated+aldehyde&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwif05eV48DWAhUKiVQKHR_-DecQsAQIJw [google.com]
returned, among other things:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRkdXuX1_5daaVSXmZcwAVPfh541fvv7kli00NcBggFqczJqwu- [gstatic.com]
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.