This domain is found in eukaryotes. This domain is about 30 amino acids in length. This domain has a single completely conserved residue Y that may be functionally important. SF3a60 makes up the SF3a complex with SF3a66 and SF3a120. This domain is the binding site of SF3a60 for SF3a120. The SF3a complex is part of the spliceosome, a protein complex involved in splicing mRNA after transcription.