This domain has been called BAH (Bromo adjacent homology) domain and has also been called ELM1 and BAM (Bromo adjacent motif) domain. The function of this domain is unknown but may be involved in protein-protein interaction [3].
PHD folds into an interleaved type of Zn-finger chelating 2 Zn ions in a similar manner to that of the RING and FYVE domains [2]. Several PHD fingers have been identified as binding modules of methylated histone H3 [3].