Manufacture and use of polypeptides tagged using binding molecules

Abstract From the Canadian patent

Molecules comprise (i) a polypeptide (such as calmodulin) which has calcium-dependent binding affinity for ligand and (ii) another polypeptide, the polypeptides preferably being joined by a peptide bond and produced by recombinant expression from a gene fusion. The molecules are useful in detection, immobilisation targeting and purification, cell-labeling and band-shift assays for determining binding of a member of a specific binding pair (sbp) for complementary sbp member. For purposes of band-shift assays polypeptide (i) need not, have calcium-dependent binding affinity for a ligand but should have a dissociation constant for a ligand of 10nM or less measured at a, pH of between 6 and 9 …