Daily Archives: June 25, 2009

Front-loading with ribosomes

While outlining the logic of front-loading in The Design Matrix, I noted how the existence of multifunctional (moonlighting) proteins would serve the needs of front-loading. In essence, a protein with multiple functions can be viewed as a protein that is packed with preadaptations ready to be more fully exploited when the proper conditions arise.

This developing paradigm has allowed me to come up with a prediction. If evolution was front-loaded, and a significant aspect of this front-loading existed as multifunctional proteins, whereby secondary or tertiary functions could be unleashed as evolution proceeded into the future, an excellent candidate for storage of some of these secondary functions would be the ribosome, the protein-synthesizing factory of the cell. This is because a designer could count on the ribosome being retained, largely unchanged, throughout billions of years of evolution because it plays such an absolutely essential role in life. If it remains largely unchanged, secondary functions can be carried into the future. Thus, I would predict that ribosomal proteins, which normally function as chaperones to fold the ribosomal RNA and hold it together to form the functioning ribosome, would also exhibit secondary functions (moonlight).

And a survey of the literature does indeed support this prediction.

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