Patent ID: 8062858

Claim:
A method for identifying or selecting a target molecule in a sample comprising: (a) contacting the sample with a fibronectin type III (Fn3) domain polypeptide monobody binding protein that binds to the target molecule under conditions that allow binding to form a target molecule-binding protein complex, wherein the target molecule is a specific binding partner, wherein the monobody comprises at least two Fn3 beta-strand domain sequences with a loop region sequence linked between each Fn3 beta-strand domain sequence, wherein at least one of the loop region sequences comprises an AB, BC, CD, DE, or FG loop region sequence that varies as compared to the wild-type (SEQ ID NO:110, FIG. 2 ) loop region sequence by deletion of two to twelve amino acids in the loop region sequence, insertion of at least two to 25 amino acids, or replacement of at least two amino acids in the loop region sequence, and wherein the loop region sequence comprises at least two amino acids; and (b) identifying or selecting the complex, thereby identifying or selecting the target molecule in the sample.