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Extending protein alphabet with non-standard amino acids and DNA/RNA alphabet with additional "letters"[1] could drive an explosive growth in the amount of poss

• gilleain 3y ago
  Possibly. However proteins already use 20 (or 21) amino acids, and do post-translational modification of these. In addition, they use cofactors, metal clusters, and other ways to tweak the chemistry they have available. As an analogy, it seem a little like a programming language - up to a point, adding more keywords and operators makes it more 'powerful' (all Turing-complete languages are equally powerful, yes). However beyond that you are just adding more specialised parts that could achieve the same thing with more, simpler parts. I guess I am saying that the leap from, say a 5 amino acid alphabet to a 20 letter one might result in an explosive growth, but it is diminishing returns after that.
  • ubiquitination 3y ago
    I think the key advantage here is adding synthetic amino acids to key sites (e.g., a binding interface). It'll be easier to modify surface chemistry that way, rather than modifying the structure of the entire protein to try and subtly alter a reaction site of interest. But yes, we are a long from adding new amino acids and DNA bases to the natural alphabet - all the molecular machines we currently have are optimised for 4 bases and 20 amino acids, it's not trivial to do it better than nature!