Life on Earth exhibits a preference for specific molecular orientations (chirality), like right-handed DNA and left-handed proteins.
This seemingly arbitrary choice has profound implications for biological interactions and the machinery of life.
Transcript:
Madeleine Finlay
Imagine you're playing a game of Tetris. You have a hole you want to fill, two squares up and one to the right. Out from the Tetris heavens emerges a suitable looking piece. Two up, but one to the left. It's the mirror image of the piece you need. And no matter how many times you flip it, it just won't fit in the hole like you'd planned. This picture actually plays out in nature. There are molecules that can exist in one form and its mirror image too. But for some mysterious reason, when it comes to life, nature prefers to pick. It likes to build, say, DNA, proteins, cells, using one orientation of a molecule or its mirror. But not both. This choice defines our whole biology. (Time 0:02:22)
Chirality's Importance
Molecular handedness determines interactions, like a left hand in a right-handed glove.
Mismatched chirality disrupts biological processes.
Transcript:
Ian Sample
Is the key point in that the handedness of the molecules is really important because it determines how they interact with other molecules. So for example, if you're a protein in the blood and you're interacting with, say, another protein, which might be like a receptor on the surface of a cell, that will work if the proteins Have the chirality that's expected, because that's how the shapes interact. They interact by their shape. If you have a protein that has the opposite chirality to normal, like trying to put your left hand into a right-handed glove it won't fit it doesn't connect in the same way and so the biological Interactions the machinery of biology starts falling apart if if if the chiralities aren't as expected (Time 0:06:53)
Mirror Life's Potential
Mirror life, composed of mirror-image molecules, could revolutionize medicine and biotechnology.
Potential applications include immune-evading drugs and virus-resistant bioreactors.
Transcript:
Madeleine Finlay
Ian, take me through the looking glass. Why would scientists want to make this stuff?
Ian Sample
So if you think about the properties that mirror molecules would have, they're really interesting. So first of all, if you could make a lot of drugs, you know, can be based on proteins these days, you can use proteins as drugs and so on. If you put a mirror protein into the body, then it's likely to be invisible to the immune system. So you might be able to develop drugs that don't trigger an immune reaction because the immune system doesn't latch onto it because the mechanism is gone. And you can extend this to, if you wanted to, let's say, if you did want to make mirror microbes, microbes that are entirely built out of mirror molecules, you could use those in things Called bioreactors. Now, bioreactors are these huge vats that some industries use where they have a vat of microbes that are churning out proteins. And these will often be therapeutic proteins for drugs. Now, those plants can sometimes be devastated because viruses infect the bacteria and kill them all off. If those bacteria are mirror bacteria, the viruses, they won't be able to do anything because they can't interact in the same way because of the difference in the chirality. So you could essentially make virus-resistant microbes for use in these bioreactors. So the potential for this technology is actually really interesting. There's no denying that. It (Time 0:08:06)
Kate Adamala's Shift
Dr. Kate Adamala, initially enthusiastic, grew concerned about mirror life's risks.
Her excitement about potential applications led her to initially dismiss concerns.
Transcript:
Madeleine Finlay
Sounds very exciting. And I know that you spoke to a scientist who was beginning to kind of develop the basis of this technology called Dr. Kate Ademala. I did.
Ian Sample
And, you know, beyond all these sort of immediate applications that you could have for mirror molecules, it could also teach scientists an awful lot of really just about the nature Of life more broadly.
Kate Adamala
We would literally be able to create life that looks very similar to our own life, but is not it, is not the same life as we had on Earth for the last almost 4 billion years. So it would be a new tree of life. It would be an incredible scientific discovery. It would let us study, form and function like we've never done before.
Madeleine Finlay
So this is really exciting. And I know that researchers can already make mirror molecules in the lab. And the idea behind this being that you would eventually use them therapeutically and they're able to evade the immune system and do their job unimpeded. But then, theoretically, you could keep going and make mirror life. This is mirror cells or microbes, which would not only have practical applications like you described, but would be incredible for understanding our biology. So how far along was all this research?
Ian Sample
It was very early days, even with vast amounts of money and a really concerted effort. I haven't come across any scientists who thought that could be done in a decade. So I think realistically, this was a goal that was really on the 30-year scale.
Kate Adamala
We were very optimistic, very excited at first, because we thought about all those good practical applications. I wasn't smart enough from the beginning to recognize all the dangers. So when we started that work, I was really excited. (Time 0:09:36)
Mirror Life's Risks
Mirror life's strengths, like immune evasion, pose severe risks if released.
Unchecked replication could devastate organisms and ecosystems.
Transcript:
Madeleine Finlay
So at what point did doubts begin to creep in about developing this research?
Ian Sample
Well, I asked Kate about this and, you know, whether it dawned on her and other scientists slowly or whether it was sort of one of those Hollywood moments where the researcher just sort Of drops their coffee and goes, oh, God. And I thought her answer to this was really interesting.
Kate Adamala
I wish there was a light bulb moment where I screamed and ran out of the lab and ran into the sunset, but that didn't happen. I was originally pretty reluctant to even acknowledge the concerns because I was obviously very excited about this project. I wanted it to work. So when people started raising those concerns to me, goal was that I'll show you you're wrong I wanted to find literature that will prove them wrong and unfortunately I was not able to
Madeleine Finlay
Find anything that would prove them wrong you know there's got to be something pretty persuasive to make a scientist who's done years of work stop doing the thing that has so many potential Benefits and also could even transform the understanding of biology. What had Kate found that was so concerning to her?
Ian Sample
Well, it's actually pretty much all of the benefits, all of the cool things that you can see as being useful about mirror molecules are actually the same things that would make you really Worried about mirror life. Now, I have to really draw this distinction because nobody really sees a problem in making mirror molecules because it's a molecule. It's not going to self-replicate. But if you think about the stuff I was saying earlier, that a mirror organism would not be recognised by your immune system, that's the concern, right? Because if you have a microbe that can replicate in an organism, a human, unchecked because immune defences are having no impact on it, then you end up with septicemia. You end up with an infection that runs right through the organism because there's nothing to stop it. And the threat we're talking about is, what if these microbes get out of a lab? They're in the soil, they get into plants, the plant defenses won't be effective against them because of the chirality difference. They get into animals. If they get into humans. The same immune systems are not geared up to fight these other-handed life forms. And so these infections could tear through people, tear through organisms completely unchecked. (Time 0:11:45)
Extraterrestrial Mirror Life?
Earth's molecular handedness might be random, not a universal rule.
Extraterrestrial life could be mirror life, raising safety concerns for future exploration.
Transcript:
Madeleine Finlay
Has been equally interesting and terrifying, Ian. But I do have one final question for you. Although the building blocks on Earth do have these particular chiralities, these particular handedness, this research has shown theoretically that it doesn't have to be this way. So could there be mirror life already out there somewhere in the universe? Absolutely.
Ian Sample
I mean, the scientific community hasn't really come down on a consensus as to why life on earth has sort of chosen the handedness of molecules that it has and certainly if you look at the Biomolecules or the sort of the precursor molecules that you find on asteroids you'll find a mix of the handedness. And if those molecules came to Earth on asteroids originally, it may have just been chance that one of those forms, one of the chiralities, took the lead, dominated. It doesn't mean the same thing happened on any other planet. Or maybe the conditions on any planet just make it easier for a certain handedness to thrive. But absolutely, yeah, I mean, the life elsewhere could be mirror life.
Madeleine Finlay
Well, we'll have to be very careful when we go out looking for it, won't we, Ian? Well, thank you so much. No (Time 0:16:44)
