MUTANT G-PROTEIN COUPLED RECEPTORS AND METHODS FOR SELECTING THEM Patent application 12/450,358 filed Mar 20, 2008
Here is an example of engineering mutants to give better thermostability of a protease. Essentially the methods are the same as the ones in this patent(different kind of activity assay) http://www.ncbi.nlm.nih.gov/pubmed/3145814
Here is a version of this type of engineering from back in 1994 http://www.ncbi.nlm.nih.gov/pubmed/7950371