• Question: Hello Sam, I'm suddenly very interested in the way you join together the amino acids! Has it got any similarity to the natural way in which polypeptides are assembled within the ribosomes? (Because human always like to imitate the nature when creating machines, such as the air plane.)

    Asked by amandazzh to Sam on 23 Jun 2014.
    • Photo: Sam Lear

      Sam Lear answered on 23 Jun 2014:

      Not really.

      Unsurprisingly we’re still quite far behind nature when it comes to chemical synthesis. The ribosome is essentially doing the same reaction as I do (the bond between the amino acids is the same whichever way you do it) but biological ‘machines’ like enzymes and ribosomes are generally very highly organized, so that the molecules that react (in this case amino acids) are forced just the right arrangement so the reaction happens very efficiently and in the exact way that you want it to.

      In the case of chemical synthesis, the amino acids and growing protein chain are essentially just floating around in solution, so the amino acid and chain have more of a task of ‘finding’ each other to react. The amino acids I use also have to be ‘protected’ to stop other parts of the them reacting when they shouldn’t (a problem the ribosome doesn’t have).

      Another major difference is that protein synthesis occurs in the ribosome in the opposite direction to how we do it, so making a protein by chemical reactions really isn’t similar to how nature does it at all.

      It is the fact that machines such as the ribosome have evolved to be ‘preorganized’ to fit the things that they react that makes them so efficient. Often when chemists are reacting molecules they take inspiration from this in a broad sense – eg when designing catalysts for chemical reactions, but nature has had millions of years to develop natural catalysts in the form of proteins and ribozymes!

      (Incidentally the methods that chemists routinely use to make proteins don’t involve any catalysts, which I find surprising.)