Triple Helix — Designing a New Molecule of Life

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."

Comments

Re:Er.

[Adambomb]

Don't make the mistake of anthropomorphizing evolution. There is no committee that considers all possible solutions and states "This is the best one". Evolution is a case of what happens happens and what doesn't die out is what's left and so considered successful.

It is entirely possible that there are much more efficient ways for life to exist or function, but are different than the way life happened to happen here on earth. Or it could be that life DID happen that way but the methodology was not optimal for the environment at the time so the DNA/RNA based forms outlived them.

Binding Affinity

[Cinnamon Whirl]

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!)

Re:PNA Too stable?

[Futile Rhetoric]

An excellent point; possibly the same reason why we're stuck with bodies which break down far too quickly -- an immortal organism simply wouldn't evolve.

Re:Good

[Anonymous Coward]

Yeah sugar-phosphate is just too scary. Lets create life based on stuff we aren't made of like lead and mercury.

Re:But was it ever there?

[MightyMartian]

I can conceive of a situation where such a molecule might actually be selected against. If the molecule were "too" stable and inhibited molecular evolution, it's quite possible that early life with essentially a "broken" system like RNA, which made events like transcription errors and insertions more likely, then it's quite possible that RNA could have won out over the technically "better" molecule simply out-evolving it.

Re:Wasn't this part of a movie plot?

[game kid]

They want to make a redheaded punk-haired girl, so it's a noble cause. ;)

Re:Sounds like razors

[sentientbeing]

Would someone tell me how this happened? We were the fucking vanguard of genetics in this country. The double helix was the DNA strand to own. Then the other guy came out with a 3 HELIX STRAND. Were we scared? Hell, no. Because we hit back with a little thing called the DNA Turbo. That's three helixes and an aloe strip. For moisture. But you know what happened next? Shut up, I'm telling you what happened--the bastards went to four strands. Now we're standing around with our cocks in our hands, selling three DNA strands and a strip. Moisture or no, suddenly we're the chumps. Well, fuck it. We're going to five helixes. Sure, we could go to four helixes next, like the competition. That seems like the logical thing to do. After all, three worked out pretty well, and four is the next number after three. So let's play it safe. Let's make a thicker aloe strip and call it the Mach3Super DNA Turbo. Why innovate when we can follow? Oh, I know why: Because we're a business, that's why!