Patent ID: 8791238

Claim:
A modified ubiquitin protein comprising a ubiquitin-like folding motif, wherein: the modified ubiquitin protein comprises substitutions of four to eight amino acids at positions Gln2, Phe4, Lys6, Gln62, Lys63, Glu64, Ser65 and Thr66 of a ubiquitin protein having the amino acid sequence of SEQ ID NO: 35 or the amino acid sequence that is encoded by SEQ ID NO: 15, wherein the modified ubiquitin protein binds to a predetermined binding partner, wherein the predetermined binding partner exhibits a binding affinity with respect to the modified ubiquitin that did not exist previously with respect to a ubiquitin polypeptide of SEQ ID NO: 35, and wherein the modified ubiquitin protein has a dissociation constant (K D ) of from 10 −5 M to 10 −12 M with respect to the binding partner.