This domain is found in Dd-STATa, a STAT protein (Signal transducer and activator of transcription A) which transcriptionally regulates cellular differentiation in Dictyostelium discoideum. The EF-hand domains predicted to contain several basic residues that lie close to the DNA backbone [1].

1: Structure of an activated Dictyostelium STAT in its DNA-unbound form. Soler-Lopez M, Petosa C, Fukuzawa M, Ravelli R, Williams JG, Muller CW; Mol Cell. 2004;13:791-804. PMID:15053873