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How would we test that the mirror antibiotics actually work without developing mirror organisms and exposing ourselves to the associated risks? They aren’t goi

How would we test that the mirror antibiotics actually work without developing mirror organisms and exposing ourselves to the associated risks? They aren’t going to be mirror copies of terrestrial organisms, there’s no guarantee that mirror copies of our antibiotics will work (AFAIK it’s actually very unlikely). Protein binding sites change when mirrored because it’s not just mirror image but a change in how the proteins twist when folding, which is why most of them are sensitive to chirality. Only very simple molecules are likely to behave the same. Stuff like bleach will still work by denaturing proteins and disrupting the bilipid layer in cell membranes but anything like tetracycline and penicilin that targets peptidoglycan enzymes or ribosomes or other complex biochemistry almost certainly won’t.

throw310822 2y ago
> Protein binding sites change when mirrored because it’s not just mirror image but a change in how the proteins twist when folding, which is why most of them are sensitive to chirality Wouldn't this pretty much rule out the synthetic creation of mirror bacteria? We should not just be able to rewrite a simple existing lifeform in mirrored version; we should recode all its proteins from scratch so that they keep their function in a mirror version, assuming that that's even possible.
- throwup238 2y ago
  Yeah I think the risk is completely overblown but after the controversy over COVID and Wuhan gain of function research, bioethics discourse seems to have taken a conservative turn. Long before we’d be able to bootstrap a fully mirrored organism we’d have to develop synthetic biotech that could easily weaponize something already scary like ebola or hendra virus. Synthetic organisms have so far been paired down versions of existing bacteria, not engineered and assembled from the ground up. Once we’re capable of the latter, mirror organisms are just one entry on a very long list of existential threats. I think the real risk in the foreseeable future is horizontal gene transfer of chiral checkpoint proteins. In order to insert even a single nontrivial D protein into the genome, we’d have to modify the proteins that make sure everything is L-handed. If those managed to escape into the wild, the results would be completely unpredictable and potentially catastrophic. Bacteria mutate and evolve much faster than mammals so if any of them develop surface proteins that are functionally equivalent but D-handed, they could become resistant to antibiotics and our immune systems.
- danwills 2y ago
  I think the folding/etc would all be mirrored as well if all the components were on mirror-chirality and the overall molecular-kinetic behavior of the result would in-theory be the same when zoomed-out too (assuming it doesn't encounter too many normal-chirality molecules I guess - would be just as dangerous to them as mirror-chirality is to us). This should mean that if the DNA is mirror (no need to alter the sequence), and the RNA/proteins/etc are as well (like 100% made of the mirror-chiral molecules), then in isolation it might work just the same as regular-life, just twisting the other way? Kinda does seem like it might be a bit arbitrary what direction things should curl in, however there are maybe aspects of how quantum-spin might interact with things that might rule out stability with mirror-chirality? I am not a QM scientist but I do find it very fascinating!
gus_massa 2y ago
Mirror antibiotics must work in mirror bacteria. Mirror proteins should fold exactly like normal proteins, but mirrored. (There may be a problem with the weak force, but I never heard it's used in biology.)
- NoMoreNicksLeft 2y ago
  Mirror symmetry breaks down in counter-intuitive ways in physics, that probably bubbles up into the chemistry side of things too. Not always, and not often. Probably just often enough to be confusing, and in this case, starkly terrifying and spirit-crushing.
  - throwawaymaths 2y ago
    > probably bubbles up into the chemistry side of things too it never has so far. many experiments have been done, including an enzyme reaction
    - NoMoreNicksLeft 2y ago
      Ok, sounds completely safe then. Go ahead and work on your mirror life frankenstein experiments, we should be good.
      - throwawaymaths 2y ago
        https://news.ycombinator.com/item?id=42408396#42408731 https://news.ycombinator.com/item?id=42408396#42408731
  - selimthegrim 2y ago
    That is a completely different thing.
    - NoMoreNicksLeft 2y ago
      Prove it. Prove that there's not some corner case where a mirrored molecule stops behaving chemically the same towards other mirrored molecules.

throw310822 2y ago

> Protein binding sites change when mirrored because it’s not just mirror image but a change in how the proteins twist when folding, which is why most of them are sensitive to chirality Wouldn't this pretty much rule out the synthetic creation of mirror bacteria? We should not just be able to rewrite a simple existing lifeform in mirrored version; we should recode all its proteins from scratch so that they keep their function in a mirror version, assuming that that's even possible.

throwup238 2y ago
Yeah I think the risk is completely overblown but after the controversy over COVID and Wuhan gain of function research, bioethics discourse seems to have taken a conservative turn. Long before we’d be able to bootstrap a fully mirrored organism we’d have to develop synthetic biotech that could easily weaponize something already scary like ebola or hendra virus. Synthetic organisms have so far been paired down versions of existing bacteria, not engineered and assembled from the ground up. Once we’re capable of the latter, mirror organisms are just one entry on a very long list of existential threats. I think the real risk in the foreseeable future is horizontal gene transfer of chiral checkpoint proteins. In order to insert even a single nontrivial D protein into the genome, we’d have to modify the proteins that make sure everything is L-handed. If those managed to escape into the wild, the results would be completely unpredictable and potentially catastrophic. Bacteria mutate and evolve much faster than mammals so if any of them develop surface proteins that are functionally equivalent but D-handed, they could become resistant to antibiotics and our immune systems.
danwills 2y ago
I think the folding/etc would all be mirrored as well if all the components were on mirror-chirality and the overall molecular-kinetic behavior of the result would in-theory be the same when zoomed-out too (assuming it doesn't encounter too many normal-chirality molecules I guess - would be just as dangerous to them as mirror-chirality is to us). This should mean that if the DNA is mirror (no need to alter the sequence), and the RNA/proteins/etc are as well (like 100% made of the mirror-chiral molecules), then in isolation it might work just the same as regular-life, just twisting the other way? Kinda does seem like it might be a bit arbitrary what direction things should curl in, however there are maybe aspects of how quantum-spin might interact with things that might rule out stability with mirror-chirality? I am not a QM scientist but I do find it very fascinating!

gus_massa 2y ago

Mirror antibiotics must work in mirror bacteria. Mirror proteins should fold exactly like normal proteins, but mirrored. (There may be a problem with the weak force, but I never heard it's used in biology.)

NoMoreNicksLeft 2y ago
Mirror symmetry breaks down in counter-intuitive ways in physics, that probably bubbles up into the chemistry side of things too. Not always, and not often. Probably just often enough to be confusing, and in this case, starkly terrifying and spirit-crushing.
- throwawaymaths 2y ago
  > probably bubbles up into the chemistry side of things too it never has so far. many experiments have been done, including an enzyme reaction
  - NoMoreNicksLeft 2y ago
    Ok, sounds completely safe then. Go ahead and work on your mirror life frankenstein experiments, we should be good.
    - throwawaymaths 2y ago
      https://news.ycombinator.com/item?id=42408396#42408731 https://news.ycombinator.com/item?id=42408396#42408731
- selimthegrim 2y ago
  That is a completely different thing.
  - NoMoreNicksLeft 2y ago
    Prove it. Prove that there's not some corner case where a mirrored molecule stops behaving chemically the same towards other mirrored molecules.