I think chirality is something most people overlook in those situations too. Even if you found a world of beings exactly like you, a perfect earth with plants and low CO2 concentrations, if their proteins have opposite chirality to yours, you’re probably going to die of prion disease.
“Oh look a perfectly human person on an earth like planet I’m sure I can take my helmet off”. Nope. You just inhaled spores or skin cells or pollen or viruses or literally anything that contains “misfolded proteins” and if any of those get at all digested they could cause your body to produce more misfolded proteins, a cycle that will eventually lead to your demise.
“Look this plant isn’t poisonous” chirality is harder to check than chemical makeup. So yeah it has vitamin B but is it the kind that could kill you? (We don’t have to worry about this much on earth because basically all life on this planet makes and uses proteins of similar chirality)
“Wow that alien sex was great” too bad there were skin cells in saliva you both exchanged/ingested (or proteins in other bodily fluids) so you’re both going to die now.
Worst part is that prions are really slow acting. You could all be chilling in this wonderful earth like home for months until around the same time you all suddenly get sick and die. There’s no cure, so there’s nothing you can do besides leave a warning for the next crew who might stop by.
Oh and the same dangers go for native life on the planet too. To them you’re made of misfolded proteins so any scavengers who eat you and maybe even predators who eat them have a chance of developing and spreading prion disease. Your bodies are basically bioweapons. Any earth crops or animals you brought with would be biohazards too.
Prion diseases are not as simple as coming into contact with a protein composed of D-amino acids.
While it’s still not fully known, it’s generally one specific type of protein PrP^C that gets transformed by PrP^Sc, converting the C to Sc, and so on.
D-amino acids also occur naturally on earth.
As for B vitamins, none include proteins as far as I remember, they’re all small(ish) molecules like biotin and folate. Also having a difference in stereochemistry with most of these vitamins, wouldn’t cause toxicity.
Obviously there are some cases of small stereochemical changes being toxic (thalidomide). But generally small changes won’t automatically make something toxic.
Prions wouldn’t work like that. They would have to be very similar, and the same chirality, as our own proteins, or else the misfold would not self-replicate like prion diseases do.
I think chirality is something most people overlook in those situations too. Even if you found a world of beings exactly like you, a perfect earth with plants and low CO2 concentrations, if their proteins have opposite chirality to yours, you’re probably going to die of prion disease.
“Oh look a perfectly human person on an earth like planet I’m sure I can take my helmet off”. Nope. You just inhaled spores or skin cells or pollen or viruses or literally anything that contains “misfolded proteins” and if any of those get at all digested they could cause your body to produce more misfolded proteins, a cycle that will eventually lead to your demise.
“Look this plant isn’t poisonous” chirality is harder to check than chemical makeup. So yeah it has vitamin B but is it the kind that could kill you? (We don’t have to worry about this much on earth because basically all life on this planet makes and uses proteins of similar chirality)
“Wow that alien sex was great” too bad there were skin cells in saliva you both exchanged/ingested (or proteins in other bodily fluids) so you’re both going to die now.
Worst part is that prions are really slow acting. You could all be chilling in this wonderful earth like home for months until around the same time you all suddenly get sick and die. There’s no cure, so there’s nothing you can do besides leave a warning for the next crew who might stop by.
Oh and the same dangers go for native life on the planet too. To them you’re made of misfolded proteins so any scavengers who eat you and maybe even predators who eat them have a chance of developing and spreading prion disease. Your bodies are basically bioweapons. Any earth crops or animals you brought with would be biohazards too.
Prion diseases are not as simple as coming into contact with a protein composed of D-amino acids.
While it’s still not fully known, it’s generally one specific type of protein PrP^C that gets transformed by PrP^Sc, converting the C to Sc, and so on.
D-amino acids also occur naturally on earth.
As for B vitamins, none include proteins as far as I remember, they’re all small(ish) molecules like biotin and folate. Also having a difference in stereochemistry with most of these vitamins, wouldn’t cause toxicity.
Obviously there are some cases of small stereochemical changes being toxic (thalidomide). But generally small changes won’t automatically make something toxic.
Prions wouldn’t work like that. They would have to be very similar, and the same chirality, as our own proteins, or else the misfold would not self-replicate like prion diseases do.