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Triple Helix — Designing a New Molecule of Life

Posted by Soulskill on from the now-with-fifty-percent-more-helix dept.

Anti-Globalism sends in this quote from Scientific American about attempts to synthesize molecules that function as well or better than the natural building blocks of life: "A molecule that some researchers study in pursuit of this vision is peptide nucleic acid (PNA), which mimics the information-storing features of DNA and RNA but is built on a proteinlike backbone that is simpler and sturdier than their sugar-phosphate backbones. ... Many studies have demonstrated PNA's suitability for modifying gene expression, mostly in molecular test-tube experiments and in cell cultures. Studies in animals have begun, as has research on ways to transform PNA into drugs that can readily enter a person's cells from the bloodstream. ... Some scientists have suggested that PNAs or a very similar molecule may have formed the basis of an early kind of life at a time before proteins, DNA and RNA had evolved. Perhaps rather than creating novel life, artificial-life researchers will be re-creating our earliest ancestors."

5 of 152 comments (clear)

  1. Re:Sounds like razors by Anonymous Coward · · Score: 2, Informative

    That pretty much sums it up.

    Attempts to create novel "life forms" using this rather than DNA are not coming any time soon. We can't even make life forms de novo using the established DNA codons.

  2. Binding Affinity by Cinnamon+Whirl · · Score: 5, Informative

    Several years ago, I worked as a chemist for a small biochemical company in the UK, making modified olignucleotides and PNA.
    IIRC, PNA had one outstanding feature: It binds to a complementary DNA strand much stronger than DNA itself (due in part to the lack of repulsion in the protein backbone. DNA's phosphate backbone is negatively charged).
    Sadly, this means that two stands of PNA will bind extremely strongly to each other, and the forces required to unpair (part of the replication process) them would require different, "stronger" enzymes - so no chance of cell division, and no chance of life. (Still sounds cool though!)

    1. Re:Binding Affinity by wormBait · · Score: 4, Informative

      Chances are that the PNA would only bind if there was a match in sequence (just like DNA only binds to complementary sequence). However, if it did bind, it would probably get stuck there and thus be effectively toxic. Nevertheless, large molecules like PNAs would be very difficult to get into a cell and would most likely be less toxic than a myriad of other well-known DNA-binders that are very toxic (eg, ethidium bromide).

  3. Re:Er. by spud603 · · Score: 4, Informative
    There's nothing in evolutionary theory that says that natural selection results in 'progress'. Nothing that says that homo sapiens are more 'progressed' than neanderthals. Same goes for elephants vs woolly mammoths. This is one of the biggest and most frustrating misconceptions out there about evolution by natural selection. I think this is what GP was referring to when mentioning anthropomorphization -- don't apply human rationality to evolutionary processes.

    That said, I agree that it seems unlikely that such a fundamental shift as switching from PNA to DNA/RNA seems unlikely to have fluked itself into existence unless there's some tradeoff in, eg, efficiency of producing the molecules, or the difference is really pretty minor after all.

  4. Re:Er. by CoderBob · · Score: 2, Informative

    Except there are plenty of vegan foods that contain protein.

    Here's the first google result for searching "vegan protein":

    http://www.vrg.org/nutrition/protein.htm

    Also, IANAV, but I did know that meat was not the only source of protein.