Sequence Boundaries Between Enzymatic Functions

The rapidly expanding protein sequence databases allow Nature's strategies for evolution of new catalysts to be deciphered.  In functionally diverse superfamilies, novel functions frequently evolve by changes in the active site residues that determine substrate specificity, with no changes in the identities/positions of the residues that direct bond breaking/making.  This simple strategy adopted and demonstrated by Nature can be used for laboratory (re)design of common enzyme scaffolds to catalyze novel reactions as well as faciitate the assignment of functions to uncharacterized enzymes discovered in genome projects.