ncoding the carrier polypeptide, and the target sequence comprises at least 2 cysteines and has the sequence of Cys-Cys-Rn, whether R is any amino acid, including both D & L forms, and n is an integer from 1-100, and wherein when n???2, each R is selected independently from every other R in the sequence, but wherein the target sequence cannot be Cys-Cys-Xaa-Xaa-Cys-Cys (SEQ. ID NO: 1) wherein Xaa