| During protein evolution the low energy normal modes are the ones that contribute the most to structural divergence. On the other hand, these motions are also the ones that are more evolutionarily conserved. Thus, the low-energy normal modes direct structural divergence and dynamical conservation. Here, I will describe a perturbed Elastic Network Model that predicts that random mutations may account for the previous observations. Structures are easier to change along the flatter potential energy curves of the lower normal modes. Also, these modes are more robust with respect to mutations, which explains its evolutionary conservation. Thus, the observed role of the lower normal modes in protein evolution is that expected from random mutations, which casts doubt on previous interpretations in terms of the effects of natural selection on functionally important normal modes. |
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