Patent ID: 7592144

Claim:
A fusion protein comprising i) a ligand-binding domain (LBD) of a protein fused between the amino- and carboxyl-terminal splicing regions of an intein in place of most or all of the endonuclease domain of the naturally-occurring form of the intein, such that the amino acid sequence of the intein differs from the amino acid sequence of the naturally-occurring form of the intein that the ability of the intein to cleave and splice a polypeptide in which the intein occurs is eliminated and ii) a bacterial auxotroph-relieving protein domain (ARPD) activatably fused, by way of one of the amino- and carboxyl-terminal splicing regions of the intein, to the LBD in such a manner that the auxotrophy-relieving function of the ARPD is greater when a ligand is bound to the LBD than when a ligand is not bound to the LBD.