I remember first learning about chirality in my biochemistry course in college, and it was definitely a mind-blower. I had already started to understand that molecules had 3d structures, but the idea (and attempting to visualize it mentally) of mirror image molecules stretched my brain significantly.
It's also still amazing to me how people first recognized this: poking around looking at the crystals that form in the bottom of a wine under a microscope, noticing that some of them were mirror images of the other, and then seperating them manually with tweezer, dissolving them into two different solutions, and demonstrating that they rotated light in opposite directions.
Chemist here.
I read this and thought it was either lies or propaganda. But after a while of pondering , it would say that the word "homochiralic" (creation-from-nothing) does a lot of heavy lifting here to make their claim technically true, if at all:
Asymmetric synthesis was already well established before 1995. Chemists like Knowles, Noyori, Sharpless, and Evans could routinely produce highly enantioenriched molecules using chiral catalysts or auxiliaries.
What made Soai's reaction different was that it did not require an external chiral source. The chiral product catalyzes its own formation, so a tiny random imbalance can be amplified into a very large enantiomeric excess.
Other examples of abiotic asymmetry, such as Pasteur's crystallization experiments and circularly polarized light, were also known earlier.
So the Nobel press release is best understood as shorthand: Soai did not discover asymmetric synthesis, but demonstrated a remarkable form of self-amplifying, spontaneous chiral symmetry breaking in an abiotic chemical system.
That helps a lot! I'm a novice learning about enzymatic synthesis. I'm not there yet, but my assumption is the target molecules (And reactants/intermediate-products) will all have specific chiralities, unlike the chemical-synthesis ones which may produce 50/50. Everything in my data structures (And the pubchem CID / ChEBI ids they reference) are chiral.
Cool, brings back some memories from grad school. Always found these types of reactions with self-reenforcing quite interesting.
Reminds me of another paper where just stirring a solution or not would determine the chirality of crystals formed and gives an idea how highly chiral environments can arise from "nothing":
I remember an offhand comment from a professor in grad school about the origin of chirality in life, he said some people had speculated it had to do with parity of the electroweak force (https://ui.adsabs.harvard.edu/abs/1985Natur.318..172T/abstra...) or something like that, but it always seemed unlikely because the energy difference due to that is so tiny that it would be hard for a single or small number of events to be biased significantly in one direction.
As a right-handed person, I find this deeply offensive and request all left-handed life be destroyed at once!!
That said, would it be possible to make "right-handed" food that is safe to eat, satisfies the psychological urge to consume food in every sensory measure, but still contributes 0 calories?
Yes, this sounds like a situation where progress in that field may have led them to go back and give more credit to the original experiments going in that direction
This is a plot point in one of my most favourite science fiction novels by Roger Zelazny... bit of a spoiler, so ROT13:
_Qbbejnlf va gur Fnaq_
which still has my favourite life situation for a protagonist (room, board, tuition and generous stipend so long as he attends his uncle's alma mater until such time as he graduates....)
I remember first learning about chirality in my biochemistry course in college, and it was definitely a mind-blower. I had already started to understand that molecules had 3d structures, but the idea (and attempting to visualize it mentally) of mirror image molecules stretched my brain significantly.
It's also still amazing to me how people first recognized this: poking around looking at the crystals that form in the bottom of a wine under a microscope, noticing that some of them were mirror images of the other, and then seperating them manually with tweezer, dissolving them into two different solutions, and demonstrating that they rotated light in opposite directions.
>Other than life itself, no one had achieved this feat.
Yeah, when you put it that way it sounds pretty impresive.
Chemist here. I read this and thought it was either lies or propaganda. But after a while of pondering , it would say that the word "homochiralic" (creation-from-nothing) does a lot of heavy lifting here to make their claim technically true, if at all:
Asymmetric synthesis was already well established before 1995. Chemists like Knowles, Noyori, Sharpless, and Evans could routinely produce highly enantioenriched molecules using chiral catalysts or auxiliaries.
What made Soai's reaction different was that it did not require an external chiral source. The chiral product catalyzes its own formation, so a tiny random imbalance can be amplified into a very large enantiomeric excess.
Other examples of abiotic asymmetry, such as Pasteur's crystallization experiments and circularly polarized light, were also known earlier.
So the Nobel press release is best understood as shorthand: Soai did not discover asymmetric synthesis, but demonstrated a remarkable form of self-amplifying, spontaneous chiral symmetry breaking in an abiotic chemical system.
That helps a lot! I'm a novice learning about enzymatic synthesis. I'm not there yet, but my assumption is the target molecules (And reactants/intermediate-products) will all have specific chiralities, unlike the chemical-synthesis ones which may produce 50/50. Everything in my data structures (And the pubchem CID / ChEBI ids they reference) are chiral.
Cool, brings back some memories from grad school. Always found these types of reactions with self-reenforcing quite interesting.
Reminds me of another paper where just stirring a solution or not would determine the chirality of crystals formed and gives an idea how highly chiral environments can arise from "nothing":
Chiral symmetry breaking in sodium chlorate crystallizaton https://doi.org/10.1126/science.250.4983.975
I remember an offhand comment from a professor in grad school about the origin of chirality in life, he said some people had speculated it had to do with parity of the electroweak force (https://ui.adsabs.harvard.edu/abs/1985Natur.318..172T/abstra...) or something like that, but it always seemed unlikely because the energy difference due to that is so tiny that it would be hard for a single or small number of events to be biased significantly in one direction.
For 1m I thought I would re learn chemistry. Then I remembered how diff it was at the uni.
Does this imply a parity violation (and thus that the weak force must somehow ultimately be in involved in the reaction)?
As a right-handed person, I find this deeply offensive and request all left-handed life be destroyed at once!!
That said, would it be possible to make "right-handed" food that is safe to eat, satisfies the psychological urge to consume food in every sensory measure, but still contributes 0 calories?
Related to this? https://en.wikipedia.org/wiki/Mirror-image_life
Yes, this sounds like a situation where progress in that field may have led them to go back and give more credit to the original experiments going in that direction
Mirror-image life obviously depends on chirality. But chirality is very relevant without it. It is a fundamental aspect of chemistry (and biology).
Yes, that should be evident from the first paragraph of each article.
This is a plot point in one of my most favourite science fiction novels by Roger Zelazny... bit of a spoiler, so ROT13:
_Qbbejnlf va gur Fnaq_
which still has my favourite life situation for a protagonist (room, board, tuition and generous stipend so long as he attends his uncle's alma mater until such time as he graduates....)
See also this discussion about this in the sci-fi series The Expanse, where a planet has bi-chiral organisms (able to use both versions of these molecules): https://www.reddit.com/r/TheExpanse/comments/i4e187/a_small_...
Chirality is quite interesting!