Engineering proteins by reconstructing evolutionary adaptive paths.

Reconstructing evolutionary adaptive paths (REAP) is a low-throughput technique used to design protein libraries that can be assayed for specific properties such as catalytic function or thermostability. This approach takes advantage of natural selection by using theoretical ancestral proteins as the foundation for library variants. REAP gives rise to smaller libraries but with a higher ratio of viable proteins than other high-throughput techniques. REAP uses analyses of ancestral sequences and signatures of functional divergence to modify extant protein sequences. This allows the experimenter to statistically evaluate which amino acid mutations in which sites within the protein are most likely to produce functional proteins having varied phenotypes.