Evolutionary modes in protein observable space: the case of Thioredoxins

In this article, we investigated the structural and dynamical evolutionary behaviour of a set of ten thioredoxin proteins as formed by three extant forms and seven resurrected ones in laboratory. Starting from the crystallographic structures, we performed all-atom molecular dynamics simulations and compare the trajectories in terms of structural and dynamical properties. Interestingly, the structural properties related to the protein density (i.e. the number of residues divided by the excluded molecular volume) well describe the protein evolutionary behaviour. Our results also suggest that the changes in sequence as occurred during the evolution have affected the protein essential motions, allowing us to discriminate between ancient and extant proteins in terms of their dynamical behaviour. Such results are yet more evident when the bacterial, archaeal and eukaryotic thioredoxins are separately analysed.