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Synthetic Molecules Emulate Enzyme Behavior

FiReaNGeL writes "Ohio State University chemists have created a synthetic catalyst that can fold its molecular structure into a specific shape for a specific job, similar to natural catalysts. In tests, the chemists caused the catalysts to twist one way or the other, either to form one chemical product or its mirror image. They confirmed the shape of the molecules at each step using techniques such as nuclear magnetic resonance spectroscopy. Being able to quickly produce a catalyst of a particular shape would be a boon for the pharmaceutical and chemical industries."

22 of 58 comments (clear)

  1. Yay! by nhstar · · Score: 3, Funny

    maybe it'll finally be cheap enough to ~cure~ things rather than just treat 'em.

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    1. Re:Yay! by Tubal-Cain · · Score: 2, Insightful

      Pharmaceutical companies can only sell a cure once. They can sell treatments indefinitely.

    2. Re:Yay! by Veggiesama · · Score: 3, Insightful

      Why does everybody always say this, hinting about the possibility of conspiracy theory cover-ups and withheld cures? Why is it so hard to believe that some people actually are searching for cures?

      If a company develops a cure for AIDS, cancer, or the common cold, then it stands to reason that the company is going to make a lot of money. While other companies are bumbling around with "treatments" and "therapies," this company is going to make a lot of short-term profit, and with the help of a patent office (or whatever equivalent), AFAIK they'll retain that virtual monopoly for decades to come.

      And if you can count on capitalism for anything, it's short-term gains.

    3. Re:Yay! by maxume · · Score: 5, Interesting

      What's more satisfying: "we don't understand the disease well enough to cure it" or "those guys with more money than me are assholes"?

      What's interesting is that research into a lot of auto immune issues is actually starting to get somewhere, so we might actually start seeing cures for stuff in the next decade or two.

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      Nerd rage is the funniest rage.
    4. Re:Yay! by sbeckstead · · Score: 2, Informative

      I appreciate your enthusiasm but that list contains not one single cure. Only prevention that is about 97% effective. Most also require booster shots to keep the protection active. If you actually contract one of those diseases we can make you as comfortable as possible and let it run it's course. But there are no cures. Pharms get paid for each person that receive those inoculations as well. Face it there is NO Financial incentive to cure a disease if you can make drugs to treat it.

  2. Not just a boon, by Anonymous Coward · · Score: 4, Interesting

    It would be the holy grail. Things like converting glucose to ATP in the body achieve ~70% efficiency. This is absolutely insane. If the scientists could accurately model and design the tertiary structure of proteins at will then they could do things like making ethanol factories using minimal energy. This is extremely significant.

    1. Re:Not just a boon, by ruinevil · · Score: 4, Informative

      Things like converting glucose to ATP in the body achieve ~70% efficiency.

      Glucose to ATP using glycolysis followed by cellular respiration using the electron transport, the most efficient process, is only about 40% efficient. The rest of the energy is released as heat, which is good for warm blooded creatures like ourselves. In babies, the brown fat makes cellular respiration even less efficient, which keeps them warm.

    2. Re:Not just a boon, by structural_biologist · · Score: 2, Informative

      Scientists have been able to design new proteins that can catalyze reactions. In two landmark papers just this year (De Novo Computational Design of Retro-Aldol Enzymes, Science 2008 319, 1387; Kemp elimination catalysts by computational enzyme design, Nature 2008 453, 190), David Baker's group at the University of Washington was able to computationally design two entirely new enzymes from scratch. Of course, there's still a lot of work to be done as these enzymes are not nearly as efficient as natural enzymes, but these breakthroughs open up many great possibilities. Here's a summary describing the results of the Science paper.

    3. Re:Not just a boon, by TheLink · · Score: 4, Interesting

      Yeah maybe someday we can upgrade to something we can adjust.

      90% efficiency when running (want to stay cool - stuff stops working well when the temperature goes up[1]), and 10% efficient when sitting on the couch watching TV - to stay warm and not get fat after eating all that junk food.

      [1] "muscles tire because they get too hot"
      http://www.wired.com/wired/archive/15.03/bemore_pr.html
      http://news.bbc.co.uk/1/hi/health/2354135.stm

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  3. a hint of deja vu by janneH · · Score: 3, Insightful

    Anyone remember catalytic antibodies - from 20 years ago - which also promised rapid engineering of "enzymes" for specific reactions. They were made by immunizing an animal with a transition state analog - under the theory that stabilizing the transition state would speed up reactions (since that is what enzymes do). Well, these "abzymes" completely revolutionized enzymology and biotechnology.....oh, wait...

    1. Re:a hint of deja vu by Rev_Frozt · · Score: 2, Insightful

      I think this is fairly clearly overhyped. They are suggesting the following:

      We can construct more flexible molecules to use as catalysts. More flexible molecules interact more easily with other molecules in the environment. Unfortunately, by reacting without selectivity, it is more likely to find unexpected side-effects. This would have no place in drug design, though it could plausibly be used in very controlled environments. Realistically, people tend to want a catalyst to take A->B, not to take A-B, C-D, E-F, G-H, B-A, etc. The laundry list of reactants makes it more difficult to control or contain the reaction and makes the "enzyme" itself more dangerous to handle. There may be some utility to this in the long run; however, at present it appears as though their chief accomplishment can be summed up in one sentence:
      "We have come up with a (complex) way to take a very simple, easy to use enzyme like TAC Polymerase and turn it into something with unknown side-effects that may or may not function as expected."

      This just looks like buggy code to me... I mean, consider Polymerase as an example. It works well because it binds very specifically to DNA and matches appropriate base pairs. If it had a significantly more flexible binding pocket, and was less choosy, what use would it really be? Who wants to use a polymerase with a high probability of generating "AAAAAAAAAAAA..." regardless of the source strand used as a basis? Who wants a transport mediator protein without directionality? I mean, the idea translates to "let's take known algorithms and just give a non-0 probability of incorrectly jumping at any control point to see what happens". I think it is clear that most algorithms just fail if someone so much as flips an if -- imagine if they removed, flipped, or added random ifs every time the algorithm was run...

      Yadda yadda more analogies...

  4. Coming soon... by BPPG · · Score: 2, Funny

    Super-powered beef cows. No hormones added.

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    What's the value of information that you don't know?
  5. I have an idea for a catalyst by Majik+Sheff · · Score: 5, Funny

    How about a catalyst that takes CO2, H2O and photon energy and converts it into sugar and oxygen? Then we could use another catalyst to convert the sugar into alcohol. *Runs off to the patent office*

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    Women are like electronics: you don't know how damaged they are until you try to turn them on.
    1. Re:I have an idea for a catalyst by Anonymous Coward · · Score: 2, Funny

      But there's a lot more to brewing drinkable beer or liquor than just feeding sugar to yeast.

      You old folk are always so picky. So long as it fucks me up, I'll drink/smoke/eat it :D

    2. Re:I have an idea for a catalyst by norpan · · Score: 2, Funny
      pfft, for beer, there're four ingredients, and one of them is water.

      Water, alcohol, taste and bubbles?

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      Opinions expressed above are mine, and not my employees'.
  6. Alternate viewpoints by bperkins · · Score: 2, Funny

    That's what the Ohio State chemists find most exciting: the molecule does not maintain only one shape.

    See, that's how I'm different. They lost me at the Rockettes.

  7. This is cool on many levels. by slimjim8094 · · Score: 2, Insightful

    At some level, it was only a matter of time: put the molecules together in the right order, and (generally) the form the right shape when left to fold by themselves.

    But synthesis of enzymes and such has interesting ramifications for medicine (can't think of any enzyme-deficient diseases off the top of my head, but there must be some)

    Now what would be *really* interesting is if they could do proteins in general. That would open up a whole world of life-saving drugs.

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    1. Re:This is cool on many levels. by sydbarrett74 · · Score: 2, Informative

      (can't think of any enzyme-deficient diseases off the top of my head, but there must be some)

      How about phenylketonuria, for one?

      --
      'He who has to break a thing to find out what it is, has left the path of wisdom.' -- Gandalf to Saruman
  8. I'm skeptical by Sethumme · · Score: 5, Insightful

    IANAC, but TFA seems to overstate the find and contains several misleading statements.

    First, they cannot "quickly produce a catalyst of a particular shape," but rather they are able to take one molecule and make it twist into either of two orientations. This isn't the holy grail of catalyst molecular engineering (to "give scientists a quick and easy way to get the catalyst that they want"); rather, it gives scientists a couple 'bonus' molecular shapes for each catalyst they synthesize. There is no indication that the ability to twist synthetic molecules means that scientists will have a significantly easier time discovering new catalysts that conform to the necessary shape. As TFA says, "[d]espite decades of research, scientists aren't sure exactly how this kind of propagation works." Why should searching for "a catalyst of a particular shape or function," involve any less trial and error than before?

    Moreover, the scientists claim that "as long as there is even a slight chemical preference for one of the hands. . . . [t]he 'flexible glove' will find a way to make a better fit, and so it will assist in specifically making one of the mirror image forms." Yet there is no proof that this "chemical preference" necessarily results in the ideal molecular arrangement of the catalyst. In fact, trying to synthesize a molecule that is capable of folding into multiple useful shapes in response to specific chemical environments seems more difficult than synthesizing individual catalysts to each handle one function independently.

    Again, I could be wrong, but I think this is only a very preliminary step in making more advanced synthetic catalysts, and not necessarily a way to design them faster.

  9. Re:It's pronounced... by Libertarian001 · · Score: 2, Informative

    Flamebait?! Are you people kidding me?! That was a Homer Simpson quote! For the freaking love of Pete. Look, here's what was written:

    "They confirmed the shape of the molecules at each step using techniques such as nuclear magnetic resonance spectroscopy."

    Good freaking grief people. Get a sense of humor.

  10. Not that special... by comm2k · · Score: 2, Informative
    As far as I can tell there are some factual errors - either because the reporter got it wrong or the researches are well.. just chemists and not biologists ;)

    Natural catalysts, such as enzymes in the human body that help us digest food, get around this problem by shape-shifting to suit the task at hand. (...)
    Natural catalysts reconfigure themselves over and over again in response to different chemical cues -- as enzymes do in the body, for example.

    Actually enzymes do a have a somewhat *fixed* fold for a specific (type of) reaction and don't just catalyse this then that etc. They can be highly selective for only one substance / functional chemical group or not. However they certainly don't reconfigure themselves (we're not talking about allosteric enzymes). The cell just produces a different set of enzymes to adjust to new conditions.

    In tests, the chemists caused the catalysts to twist one way or the other, either to form one chemical product or its mirror image.

    They better have this working 'error-free'. Having a mixture of both shapes can get you into big trouble (http://en.wikipedia.org/wiki/Thalidomide).

    "For many chemical reactions to work, molecules must be able to fit a catalyst like a hand fits a glove," RajanBabu said. "Our synthetic molecules are special because they're flexible. It doesn't matter if the hand is a small hand or a big hand, the 'glove' will change its shape to fit it, as long as there is even a slight chemical preference for one of the hands. The 'flexible glove' will find a way to make a better fit, and so it will assist in specifically making one of the mirror image forms."

    I'm not sure this is so good - wouldn't you want them to behave like enzymes aswell, being highly selective? And last but not least there is no comparison offered to *real* enzymes in terms of 'speed' and what kind of reactions besides fatty acid hydrogenation are possible.

    1. Re:Not that special... by fearofcarpet · · Score: 2, Informative

      I'm sorry, I just can't let this one go... I may just be a lowly organic chemist, but there is nothing static about an enzyme. First, the obvious--conformational changes in response to pH, phosphorylation, ionic strength, etc. that turn on, turn off, or alter the functionality of an enzyme. And the even more obvious--the typical behavior of an enzyme is to alter conformation dynamically to stabilize transition states which lowers the activation barrier between two thermodynamic minima--the definition of a catalyst. The whole point of an enzyme is that the active site can accommodate a starting material, alter its conformation to stabilize the transition state that leads to the desired product, then shift again to release it. Traditional synthetic homogeneous catalysts are a trade off between specificity (e.g., stereoselectivity, substrate specificity) and efficiency (e.g., turnover number, rate). People have made entire careers out of designing Lewis acids that stereospecific, for example. Enzymes get around this trade-off precisely because they can dynamically change their conformations.

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