About the combinatorial number of 150 amino acid proteins, I think the calculation don't make sense. Nobody expect to get a 100% functional 150 amino acid protein by chance. In particular I don't like:
> He estimated that, of all 150-link amino acid sequences, 1 in 1074 will be capable of folding into a stable protein.
Is there a link for that calculation? Most random "proteins" fold as some kind of unuseful crap. But IIRC it's stable unuseful crap. Perhaps it's not soluble, perhaps it's not active as a enzyme, but it will not self destroy or something.
And there are smaller and bigger proteins. Probably the first proteins were only a few amono acid long, and not very effective, and then they evolved into more long and efective versions. See for example
> The smallest human protein is 44 amino acids but it could be an abortive translation from the 5' UTR of another mRNA. The smallest functional polypeptide is glutathione with only three amino acids.
About the combinatorial number of 150 amino acid proteins, I think the calculation don't make sense. Nobody expect to get a 100% functional 150 amino acid protein by chance. In particular I don't like:
> He estimated that, of all 150-link amino acid sequences, 1 in 1074 will be capable of folding into a stable protein.
Is there a link for that calculation? Most random "proteins" fold as some kind of unuseful crap. But IIRC it's stable unuseful crap. Perhaps it's not soluble, perhaps it's not active as a enzyme, but it will not self destroy or something.
And there are smaller and bigger proteins. Probably the first proteins were only a few amono acid long, and not very effective, and then they evolved into more long and efective versions. See for example
From https://www.science20.com/princerain/blog/whats_biggest_and_...
> The smallest human protein is 44 amino acids but it could be an abortive translation from the 5' UTR of another mRNA. The smallest functional polypeptide is glutathione with only three amino acids.
(more info https://en.wikipedia.org/wiki/Glutathione )
From https://www.science20.com/princerain/blog/smallest_protein
> Apparently it's TRP-Cage, a protein with only 20 amino acids derived from the saliva of Gila monsters.
(more info https://www.anaspec.com/products/product.asp?id=59018 )
One family of proteins that has a clear history of evolving between species is the hemoglobin-like proteins https://en.wikipedia.org/wiki/Globin