COOPERATIVELY FOLDED PROTEINS IN RANDOM SEQUENCE LIBRARIES

The structural properties of proteins recovered from random sequence l ibraries can be used to investigate the relationship between folding a nd sequence information. Here, we show that helical proteins displayin g cooperative thermal denaturation transitions can be easily recovered from a library containing 80-residue proteins predominantly composed of glutamine, leucine, and arginine, with an average hydophobicity lev el similar to that of natural proteins. The native structure of one of these proteins has a stability and oligomeric form similar to that of many natural proteins but differs in having no slowly exchanging amid e hydrogens.