Quote (El1te @ Jun 9 2023 05:54pm)
I'd be interested to know more about this. Although I presume this protein evolution is genetically directed
Note that this is not an explation of the origin of proteins, this assumes a protein already exists to evolve. We don't know how proteins came about as part of living organisms, but there are theories with compelling evidence.
Take a gene that makes a protein. Copy it. This happens pretty often.
Now mutate the promoter ahead of that gene so it isn't expressed. This turns off one of the copies of the protein.
Now, let it sit there for many generations and acquire random mutations.
Now due to random mutations, sometime down the line that promoter gets mutated back to be expressed again. It is now altered from the original. If it causes harm, the individual is disfavored and doesn't manage to mate. Maybe it mutated in a way to cause cells to die, or something. If it does something beneficial, like the same job as a different protein but more efficiently, it is kept around and that individual reproduces more efficiently. That protein now goes through the population as part of sexual reproduction.
You can do this with lots of proteins to get disparate functions from similar structures, and it's been observed in the genomes of related species. It's also how you get a similar mechanism for a flagella as the ATP pump, and explains why there's homology in those cases.
This has been studied to death in the past ~30 years and we have very strong evidence for this and other mechanisms of protein mutation.