Recent years have seen increasing awareness of the evolutionary role of active site loop dynamics , as well as the implications of this for enzyme engineering . PTPs are an excellent model system to probe this, as there is both computational and experimental evidence suggesting a direct link between the dynamics of the active-site WPD-loop and the turnover rate of these enzymes. Furthermore, these enzymes are biomedically important but extremely challenging drug targets, in particular for the development of novel cancer therapeutics, and the design of allosteric inhibitors that can impair proper closure of the WPD-loop remains a promising avenue for drug discovery efforts targeting these enzymes .