How far divergent evolution goes in proteins

In theory, mutations of protein sequences may eventually generate different functions as well as different structures. The observation of such records of protein evolution have been obscured by the dissipation of memory about the ancestors. In the past year, new advances in our understanding of divergent evolution were allowed by new protein structure determinations, including the ClpP proteases, steroid delta-isomerase, carboxypeptidase G2, the thrombin inhibitor triabin and the chloroplast Rieske protein. There is strong evidence for their distant homology with proteins of known structure despite significant functional or structural differences.