A protein is created in the cell by copying its DNA gene, making any necessary edits to the copy, and passing the copy to the ribosome machine which uses the genetic code to translate the copy (a series of nucleotides) into the protein structure (a series of amino acids). But the story does not end here. The final step, after translation, is to fold the protein into its three dimensional structure. It is a step that is difficult to monitor and difficult to predict. The chain of amino acids folds up in a tiny fraction of a second and the final shape it assumes is not obvious. And sometimes the folding process is literally hidden as the nascent protein chain is hidden inside the cavity of a chaperonin machine with the lid shut.
Chaperonins are large protein machines that help some proteins to fold into their proper shape. New research is reporting on the structure of a particular chaperonin, including the lid closing action. The results are fascinating and they raise the question of how and why such an intricate protein machine evolved.
The different types of chaperonins fall into the broader category of molecular machines that not only help new proteins to fold, but also help existing proteins recover from shock, help with the assembly of machines, and so forth.
The obvious question is: How could evolution just happen to produce such machines? After all, a long series of lucky mutations would be required. But a more subtle problem has to do with not how, but why evolution would produce such machines.
For instance, this chaperonin machine, even if somehow was created by the cell, helps fold proteins that don’t want to fold very often. So before the helper chaperonin machine was available, these reluctant proteins would be lying around in various useless forms. For all we know they might be unfolded, or they might be misfolded. In any case, they would be clogging the works.
According to evolution these reluctant proteins would decrease fitness and not be selected. They would be evolutionary dead ends.
But in that case the chaperonin helper machines, when they just happened to evolve, would have nothing to do. Again, according to evolution, they would be consuming energy, getting in the way, and generally not helping. They too would not be selected.
These are questions that young evolutionists are prone to ask (evolutionists are constantly probing and trying to falsify their own theory). In their lack of experience they miss the obvious solution: Evolution simultaneously evolved both the chaperonins and the proteins that need their help. The reluctant proteins were never clogging the works, and the chaperonins never lacked for something to do. Evolution’s timing was perfect. As usual evolution provides an answer that is simple, elegant and compelling. You can see why it is said to be a fact.
