The engineered Forkhead-associated Domain (FHA1), located at the N-terminus of the RAD53 protein of Saccharomyces cerevisiae, was shown in previous studies to specifically recognize the phosphorylated peptide of the p53-binding protein (53BP1). When the engineered FHA1 domain was expressed as a recombinant rabbit Fc-fusion protein, it still recognized the phosphorylated 53BP1 peptide in an ELISA. FHA1-Fc fusion proteins can thus be used as specific antibodies to identify the phosphorylation status of various proteins.
Thota et al. (Tue,) studied this question.